Vulnerability-Lookup

OPENSUSE-SU-2026:20773-1

Vulnerability from csaf_opensuse - Published: 2026-05-19 16:18 - Updated: 2026-09-17 17:32

Summary

Security update for perl-Net-CIDR

Severity

Important

Notes

Title of the patch: Security update for perl-Net-CIDR

Description of the patch: This update for perl-Net-CIDR fixes the following issues: Changes in perl-Net-CIDR: - updated to 0.270.0 (0.27) 0.27 Sam Varshavchik cidrvalidate() bug fix. - updated to 0.260.0 (0.26) 0.26 Sam Varshavchik cidrvalidate() should accept IPv6 addresses with one uncompressed 0. - updated to 0.250.0 (0.25) 0.25 Sam Varshavchik Fix warning with Perl 5.40 0.24.1 No changes, re-pushed due to a release problem. 0.24 2025-03-09 brian d foy * Strip leading zeros from octets from addr2cidr bsc#1259024 CVE-2021-4456 - updated to 0.230.0 (0.23) 0.23 2025-03-09 brian d foy * Allow unabbreviated IPv6 addresses. 0.22 2025-03-09 Sam Varshavchik * Improve several error messages. 2025-03-09 brian d foy * Allow unabbreviated IPv6 addresses.

Patchnames: openSUSE-Leap-16.0-packagehub-265

CVE-2021-4456

8.2 (High)


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

Affected products

Recommended 1 product

Product	Identifier	Version	Remediation
Unresolved product id: openSUSE Leap 16.0:perl-Net-CIDR-0:0.270.0-bp160.1.1.noarch		—	Vendor Fix

Threats

Impact important

References

6 references

URL	Category
https://www.suse.com/support/security/rating/	external
https://ftp.suse.com/pub/projects/security/csaf/o…	self
https://bugzilla.suse.com/1259024	self
https://www.suse.com/security/cve/CVE-2021-4456/	self
https://www.suse.com/security/cve/CVE-2021-4456	external
https://bugzilla.suse.com/1259024	external

JSON

To clipboard

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      "text": "important"
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        "text": "This update for perl-Net-CIDR fixes the following issues:\n\nChanges in perl-Net-CIDR:\n\n- updated to 0.270.0 (0.27)\n  0.27\tSam Varshavchik\n\tcidrvalidate() bug fix.\n\n- updated to 0.260.0 (0.26)\n  0.26    Sam Varshavchik\n\tcidrvalidate() should accept IPv6 addresses with one uncompressed 0.\n\n- updated to 0.250.0 (0.25)\n  0.25    Sam Varshavchik\n\tFix warning with Perl 5.40\n  0.24.1\n\tNo changes, re-pushed due to a release problem.\n  0.24\n  2025-03-09   brian d foy\n\t* Strip leading zeros from octets from addr2cidr\n    bsc#1259024 CVE-2021-4456\n\n- updated to 0.230.0 (0.23)\n  0.23\n  2025-03-09   brian d foy\n\t* Allow unabbreviated IPv6 addresses.\n  0.22\n  2025-03-09  Sam Varshavchik\n\t* Improve several error messages.\n  2025-03-09   brian d foy\n\t* Allow unabbreviated IPv6 addresses.\n",
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        "title": "Patchnames"
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        "url": "https://www.suse.com/security/cve/CVE-2021-4456/"
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    "title": "Security update for perl-Net-CIDR",
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          "number": "1",
          "summary": "Current version"
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          "date": "2026-09-16T20:35:13Z",
          "number": "2",
          "summary": "unknown changes"
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          "date": "2026-09-16T21:38:14Z",
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      ],
      "notes": [
        {
          "category": "general",
          "text": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.\n\nThe functions `addr2cidr` and `cidrlookup` may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.\n\nThe documentation advises validating untrusted CIDR strings with the `cidrvalidate` function. However, this mitigation is optional and not enforced by default. In practice, users may call `addr2cidr` or `cidrlookup` with untrusted input and without validation, incorrectly assuming that this is safe.",
          "title": "CVE description"
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      "remediations": [
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            "openSUSE Leap 16.0:perl-Net-CIDR-0:0.270.0-bp160.1.1.noarch"
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    }
  ]
}

CVE-2021-4456 (GCVE-0-2021-4456)

Vulnerability from cvelistv5 – Published: 2026-02-27 00:16 – Updated: 2026-02-27 16:53

Title

Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact

Summary

Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact. The functions `addr2cidr` and `cidrlookup` may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses. The documentation advises validating untrusted CIDR strings with the `cidrvalidate` function. However, this mitigation is optional and not enforced by default. In practice, users may call `addr2cidr` or `cidrlookup` with untrusted input and without validation, incorrectly assuming that this is safe.

Severity

6.5 (Medium)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-02-27 16:52 UTC

CWE

CWE-704 - Incorrect Type Conversion or Cast

Assigner

CPANSec redhat root Scorecard

References

3 references

URL	Tags
https://blog.urth.org/2021/03/29/security-issues-…	related
https://github.com/svarshavchik/Net-CIDR/commit/e…	patch
https://metacpan.org/dist/Net-CIDR/changes	release-notes

Impacted products

1 product

Vendor	Product	Version
MRSAM	Net::CIDR	Affected: 0 , < 0.24 (custom)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "NONE",
              "baseScore": 6.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "LOW",
              "integrityImpact": "LOW",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-4456",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-02-27T16:52:58.903437Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-02-27T16:53:23.671Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "packageName": "Net-CIDR",
          "product": "Net::CIDR",
          "programRoutines": [
            {
              "name": "addr2cidr"
            },
            {
              "name": "cidrlookup"
            }
          ],
          "repo": "https://github.com/svarshavchik/Net-CIDR",
          "vendor": "MRSAM",
          "versions": [
            {
              "lessThan": "0.24",
              "status": "affected",
              "version": "0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact.\n\nThe functions `addr2cidr` and `cidrlookup` may return leading zeros in a CIDR string, which may in turn be parsed as octal numbers by subsequent users. In some cases an attacker may be able to leverage this to bypass access controls based on IP addresses.\n\nThe documentation advises validating untrusted CIDR strings with the `cidrvalidate` function. However, this mitigation is optional and not enforced by default. In practice, users may call `addr2cidr` or `cidrlookup` with untrusted input and without validation, incorrectly assuming that this is safe."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-704",
              "description": "CWE-704 Incorrect Type Conversion or Cast",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-27T00:16:36.383Z",
        "orgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
        "shortName": "CPANSec"
      },
      "references": [
        {
          "tags": [
            "related"
          ],
          "url": "https://blog.urth.org/2021/03/29/security-issues-in-perl-ip-address-distros/"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/svarshavchik/Net-CIDR/commit/e3648c6bc6bdd018f90cca4149c467017d42bd10"
        },
        {
          "tags": [
            "release-notes"
          ],
          "url": "https://metacpan.org/dist/Net-CIDR/changes"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "value": "Use the `cidrvalidate` function on untrusted input before passing to the affected functions or upgrade to version 0.24 or later"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Net::CIDR versions before 0.24 for Perl mishandle leading zeros in IP CIDR addresses, which may have unspecified impact",
      "x_generator": {
        "engine": "cpansec-cna-tool 0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
    "assignerShortName": "CPANSec",
    "cveId": "CVE-2021-4456",
    "datePublished": "2026-02-27T00:16:36.383Z",
    "dateReserved": "2025-05-18T22:36:11.463Z",
    "dateUpdated": "2026-02-27T16:53:23.671Z",
    "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.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

OPENSUSE-SU-2026:20773-1

CVE-2021-4456 (GCVE-0-2021-4456)

Tags

Sightings

Nomenclature

Related by attack behaviour