CVE-2026-74545 (GCVE-0-2026-74545)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:27 – Updated: 2026-08-17 05:48
VLAI
Title
rtase: fix double free of multi-frag skb on DMA map failure
Summary
In the Linux kernel, the following vulnerability has been resolved: rtase: fix double free of multi-frag skb on DMA map failure In rtase_start_xmit(), when the head buffer DMA mapping fails after rtase_xmit_frags() has mapped all fragments, the error path clears the fragment descriptors with rtase_tx_clear_range(), which frees the skb through the last-frag slot and accounts tx_dropped. Control then falls through to the common error label, which frees the same skb a second time and counts it again. Return right after clearing the fragments when the skb owns frags; the no-frag case still drops through and frees the head skb once.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: d6e882b89fdf80be0ab4f914ec10f75215e49495 , < 4f09172aff5f73a5e914f4fbc0d00a1c2ea9f7cb (git)
Affected: d6e882b89fdf80be0ab4f914ec10f75215e49495 , < db986098f30881fafcc752800aa3b13fd289c922 (git)
Affected: d6e882b89fdf80be0ab4f914ec10f75215e49495 , < de691dc3227b061c4d0beba9f0128fe1ff33dd68 (git)
Affected: d6e882b89fdf80be0ab4f914ec10f75215e49495 , < 6fb7b769d6ed6d1d2e02af4a80e57a2477f35086 (git)
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Linux Linux Affected: 6.12
Unaffected: 0 , < 6.12 (semver)
Unaffected: 6.12.103 , ≤ 6.12.* (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/realtek/rtase/rtase_main.c"
          ],
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrtase: fix double free of multi-frag skb on DMA map failure\n\nIn rtase_start_xmit(), when the head buffer DMA mapping fails after\nrtase_xmit_frags() has mapped all fragments, the error path clears\nthe fragment descriptors with rtase_tx_clear_range(), which frees\nthe skb through the last-frag slot and accounts tx_dropped. Control\nthen falls through to the common error label, which frees the same\nskb a second time and counts it again.\n\nReturn right after clearing the fragments when the skb owns frags;\nthe no-frag case still drops through and frees the head skb once."
        }
      ],
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            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
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              "lang": "en",
              "value": "AV:N - The flaw is in rtase_start_xmit (ndo_start_xmit) on the Realtek Automotive Switch PCIe netdev; a remote peer can reach it by sending traffic that the host forwards, bridges, or answers out the rtase interface on automotive gateways and industrial routers without local shell access.\nAC:L - NETIF_F_SG enables multi-fragment TX skbs that rtase_xmit_frags maps before the head; an attacker can reliably create such packets and pressure SWIOTLB/IOVA resources with concurrent egress so the final head dma_map_single fails after fragment mapping succeeds, deterministically hitting the buggy error path.\nPR:N - Exploitation needs only the ability to inject or induce network traffic transmitted via the rtase netdev; no target credentials, capabilities, or local account are required on forwarding automotive/industrial gateways where this driver is deployed.\nUI:N - No victim interaction is required; the double free occurs automatically when the kernel queues a multi-fragment skb and the head DMA mapping fails during normal transmit error handling.\nS:U - The double free corrupts kernel heap allocator state on the host running the rtase driver; it does not cross VM, container, or IOMMU security boundaries.\nC:H - Double-freeing the same skb is kernel heap memory corruption that can corrupt freelist metadata and enable reuse of freed skb memory for arbitrary kernel memory disclosure, not merely a bounded leak.\nI:H - Heap corruption from freeing the same skb twice can be shaped into arbitrary kernel memory writes or control-flow hijacking via slab reuse, not limited to dropping a single packet.\nA:H - Double-freeing an skb reliably corrupts the slab allocator and can trigger immediate oops, panic, or watchdog reset; the attacker can repeat multi-fragment transmits under DMA pressure for sustained denial of service on safety-critical automotive networks."
            }
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        "dateUpdated": "2026-08-17T05:48:32.121Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "datePublished": "2026-08-15T12:27:54.536Z",
    "dateReserved": "2026-08-15T05:44:03.914Z",
    "dateUpdated": "2026-08-17T05:48:32.121Z",
    "state": "PUBLISHED"
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrtase: fix double free of multi-frag skb on DMA map failure\n\nIn rtase_start_xmit(), when the head buffer DMA mapping fails after\nrtase_xmit_frags() has mapped all fragments, the error path clears\nthe fragment descriptors with rtase_tx_clear_range(), which frees\nthe skb through the last-frag slot and accounts tx_dropped. Control\nthen falls through to the common error label, which frees the same\nskb a second time and counts it again.\n\nReturn right after clearing the fragments when the skb owns frags;\nthe no-frag case still drops through and frees the head skb once."
          }
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        "lastModified": "2026-08-17T06:19:51.713",
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        "vulnStatus": "Received"
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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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.
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  • 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.



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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.