CVE-2026-89950 (GCVE-0-2026-89950)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:32 – Updated: 2026-09-16 10:32
VLAI
Title
batman-adv: mcast: linearize skbuff for packet generation
Summary
In the Linux kernel, the following vulnerability has been resolved: batman-adv: mcast: linearize skbuff for packet generation batadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only called (indirectly) by the unsharing+linearizing batadv_recv_mcast_packet() handler. When it is called (indirectly) by batadv_mcast_forw_mcsend() then it will be unshared but not linearized. The SKB_LINEAR_ASSERT() can therefore cause a fatal BUG(). The linearization should happen during the expansion of the head because the scrape function can be hit already during the initial batadv_mcast_forw_mode() selection code: * batadv_interface_tx * batadv_mcast_forw_mode * batadv_mcast_forw_mode_by_count() * batadv_mcast_forw_push() -> calls batadv_mcast_forw_expand_head() before everything else * batadv_mcast_forw_push_tvlvs() * batadv_mcast_forw_push_dests() * batadv_mcast_forw_push_adjust_padding() * batadv_mcast_forw_scrape()
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 90039133221e33964ccb4a536dad7eb0a372fff7 , < a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e (git)
Affected: 90039133221e33964ccb4a536dad7eb0a372fff7 , < c32e5e25c41201c8c3b796a4ab2c45103187091e (git)
Affected: 90039133221e33964ccb4a536dad7eb0a372fff7 , < 2879177539e3ece483a8e5406970373698e9a6c5 (git)
Affected: 90039133221e33964ccb4a536dad7eb0a372fff7 , < 6a30a59e2660afd03c975f1b8eae6a2301161197 (git)
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Linux Linux Affected: 6.8
Unaffected: 0 , < 6.8 (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.51 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/batman-adv/multicast_forw.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "6.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: mcast: linearize skbuff for packet generation\n\nbatadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only\ncalled (indirectly) by the unsharing+linearizing batadv_recv_mcast_packet()\nhandler. When it is called (indirectly) by batadv_mcast_forw_mcsend() then\nit will be unshared but not linearized. The SKB_LINEAR_ASSERT() can\ntherefore cause a fatal BUG().\n\nThe linearization should happen during the expansion of the head because\nthe scrape function can be hit already during the initial\nbatadv_mcast_forw_mode() selection code:\n\n* batadv_interface_tx\n* batadv_mcast_forw_mode\n* batadv_mcast_forw_mode_by_count()\n* batadv_mcast_forw_push()\n  -\u003e calls batadv_mcast_forw_expand_head() before everything else\n* batadv_mcast_forw_push_tvlvs()\n* batadv_mcast_forw_push_dests()\n* batadv_mcast_forw_push_adjust_padding()\n* batadv_mcast_forw_scrape()"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T10:32:35.485Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a9603e0a7cb5e0cddc6b23af153cf7daafc5c55e"
        },
        {
          "url": "https://git.kernel.org/stable/c/c32e5e25c41201c8c3b796a4ab2c45103187091e"
        },
        {
          "url": "https://git.kernel.org/stable/c/2879177539e3ece483a8e5406970373698e9a6c5"
        },
        {
          "url": "https://git.kernel.org/stable/c/6a30a59e2660afd03c975f1b8eae6a2301161197"
        }
      ],
      "title": "batman-adv: mcast: linearize skbuff for packet generation",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89950",
    "datePublished": "2026-09-16T10:32:35.485Z",
    "dateReserved": "2026-09-11T19:38:34.777Z",
    "dateUpdated": "2026-09-16T10:32:35.485Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
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      "date": "2026-09-25",
      "epss": "0.00209",
      "percentile": "0.09825"
    },
    "nvd": {
      "cve": {
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            "affectedData": [
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                "product": "Linux",
                "programFiles": [
                  "net/batman-adv/multicast_forw.c"
                ],
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                ],
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                    "versionType": "semver"
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                    "version": "6.18.51",
                    "versionType": "semver"
                  },
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                    "lessThanOrEqual": "7.2.*",
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                    "version": "7.2.5",
                    "versionType": "semver"
                  },
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                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: mcast: linearize skbuff for packet generation\n\nbatadv_mcast_forw_packet() and batadv_mcast_forw_scrape() is not only\ncalled (indirectly) by the unsharing+linearizing batadv_recv_mcast_packet()\nhandler. When it is called (indirectly) by batadv_mcast_forw_mcsend() then\nit will be unshared but not linearized. The SKB_LINEAR_ASSERT() can\ntherefore cause a fatal BUG().\n\nThe linearization should happen during the expansion of the head because\nthe scrape function can be hit already during the initial\nbatadv_mcast_forw_mode() selection code:\n\n* batadv_interface_tx\n* batadv_mcast_forw_mode\n* batadv_mcast_forw_mode_by_count()\n* batadv_mcast_forw_push()\n  -\u003e calls batadv_mcast_forw_expand_head() before everything else\n* batadv_mcast_forw_push_tvlvs()\n* batadv_mcast_forw_push_dests()\n* batadv_mcast_forw_push_adjust_padding()\n* batadv_mcast_forw_scrape()"
          }
        ],
        "id": "CVE-2026-89950",
        "lastModified": "2026-09-16T11:17:05.160",
        "metrics": {},
        "published": "2026-09-16T11:17:05.160",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/2879177539e3ece483a8e5406970373698e9a6c5"
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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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.

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.



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.