CVE-2026-31657 (GCVE-0-2026-31657)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:45 – Updated: 2026-04-24 14:45
VLAI?
Title
batman-adv: hold claim backbone gateways by reference
Summary
In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by reference batadv_bla_add_claim() can replace claim->backbone_gw and drop the old gateway's last reference while readers still follow the pointer. The netlink claim dump path dereferences claim->backbone_gw->orig and takes claim->backbone_gw->crc_lock without pinning the underlying backbone gateway. batadv_bla_check_claim() still has the same naked pointer access pattern. Reuse batadv_bla_claim_get_backbone_gw() in both readers so they operate on a stable gateway reference until the read-side work is complete. This keeps the dump and claim-check paths aligned with the lifetime rules introduced for the other BLA claim readers.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 23721387c409087fd3b97e274f34d3ddc0970b74 , < f4858832ddef2f39f21e30b7226bbcd3c4b2bc96 (git)
Affected: 23721387c409087fd3b97e274f34d3ddc0970b74 , < 2f55b58b5a0bbed192d60c444a45a49cdf1b545f (git)
Affected: 23721387c409087fd3b97e274f34d3ddc0970b74 , < 7962b522222628596ca9ecc8722efc95367aadbd (git)
Affected: 23721387c409087fd3b97e274f34d3ddc0970b74 , < 4dee4c0688443aaf5bbec74aa203c851d1d53c35 (git)
Affected: 23721387c409087fd3b97e274f34d3ddc0970b74 , < 1f2dc36c297d27733f1b380ea644cf15a361bd7b (git)
Affected: 23721387c409087fd3b97e274f34d3ddc0970b74 , < 82d8701b2c930d0e96b0dbc9115a218d791cb0d2 (git)
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    Linux Linux Affected: 3.5
Unaffected: 0 , < 3.5 (semver)
Unaffected: 6.1.169 , ≤ 6.1.* (semver)
Unaffected: 6.6.135 , ≤ 6.6.* (semver)
Unaffected: 6.12.82 , ≤ 6.12.* (semver)
Unaffected: 6.18.23 , ≤ 6.18.* (semver)
Unaffected: 6.19.13 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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            "net/batman-adv/bridge_loop_avoidance.c"
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              "version": "6.18.23",
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        }
      ],
      "cpeApplicability": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: hold claim backbone gateways by reference\n\nbatadv_bla_add_claim() can replace claim-\u003ebackbone_gw and drop the old\ngateway\u0027s last reference while readers still follow the pointer.\n\nThe netlink claim dump path dereferences claim-\u003ebackbone_gw-\u003eorig and\ntakes claim-\u003ebackbone_gw-\u003ecrc_lock without pinning the underlying\nbackbone gateway. batadv_bla_check_claim() still has the same naked\npointer access pattern.\n\nReuse batadv_bla_claim_get_backbone_gw() in both readers so they operate\non a stable gateway reference until the read-side work is complete.\nThis keeps the dump and claim-check paths aligned with the lifetime\nrules introduced for the other BLA claim readers."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-04-24T14:45:08.867Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/2f55b58b5a0bbed192d60c444a45a49cdf1b545f"
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        },
        {
          "url": "https://git.kernel.org/stable/c/82d8701b2c930d0e96b0dbc9115a218d791cb0d2"
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    "cveId": "CVE-2026-31657",
    "datePublished": "2026-04-24T14:45:08.867Z",
    "dateReserved": "2026-03-09T15:48:24.129Z",
    "dateUpdated": "2026-04-24T14:45:08.867Z",
    "state": "PUBLISHED"
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  }
}


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  • 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 patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.