{"id":"CVE-2026-31659","state":"PUBLISHED","title":"batman-adv: reject oversized global TT response buffers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: reject oversized global TT response buffers\n\nbatadv_tt_prepare_tvlv_global_data() builds the allocation length for a\nglobal TT response in 16-bit temporaries. When a remote originator\nadvertises a large enough global TT, the TT payload length plus the VLAN\nheader offset can exceed 65535 and wrap before kmalloc().\n\nThe full-table response path still uses the original TT payload length when\nit fills tt_change, so the wrapped allocation is too small and\nbatadv_tt_prepare_tvlv_global_data() writes past the end of the heap object\nbefore the later packet-size check runs.\n\nFix this by rejecting TT responses whose TVLV value length cannot fit in\nthe 16-bit TVLV payload length field.","publishedAt":"2026-04-24T14:45:10.254Z","updatedAt":"2026-10-19T18:56:02.093Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"7e5d007e0df946bffb8542fb112e0044014a5897","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"2997f4bd1f982e7013709946e00be89b507693fa","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"95c71365a2222908441b54d6f2c315e0c79fcec3","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"69d61639bc7e963c3b645e570279d731e7c89062","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"f970646b9a39539d1bac86822ac78b5915455ea9","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"de6c1dc3c7d01a152607e6fcecee4d5288283f10","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"cf2199171ef799ca7270019125f4a91bd20ad4d9","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"3a359bf5c61d52e7f09754108309d637532164a6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/translation-table.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.13","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.169","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.135","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.82","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.23","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.13","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/translation-table.c"]}],"references":["https://git.kernel.org/stable/c/7e5d007e0df946bffb8542fb112e0044014a5897","https://git.kernel.org/stable/c/2997f4bd1f982e7013709946e00be89b507693fa","https://git.kernel.org/stable/c/95c71365a2222908441b54d6f2c315e0c79fcec3","https://git.kernel.org/stable/c/69d61639bc7e963c3b645e570279d731e7c89062","https://git.kernel.org/stable/c/f970646b9a39539d1bac86822ac78b5915455ea9","https://git.kernel.org/stable/c/de6c1dc3c7d01a152607e6fcecee4d5288283f10","https://git.kernel.org/stable/c/cf2199171ef799ca7270019125f4a91bd20ad4d9","https://git.kernel.org/stable/c/3a359bf5c61d52e7f09754108309d637532164a6"],"weaknesses":["CWE-190"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/31xxx/CVE-2026-31659.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-31659","state":"PUBLISHED","datePublished":"2026-04-24T14:45:10.254Z","dateUpdated":"2026-10-19T18:56:02.093Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-03-09T15:48:24.129Z"},"containers":{"cna":{"title":"batman-adv: reject oversized global TT response buffers","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: reject oversized global TT response buffers\n\nbatadv_tt_prepare_tvlv_global_data() builds the allocation length for a\nglobal TT response in 16-bit temporaries. When a remote originator\nadvertises a large enough global TT, the TT payload length plus the VLAN\nheader offset can exceed 65535 and wrap before kmalloc().\n\nThe full-table response path still uses the original TT payload length when\nit fills tt_change, so the wrapped allocation is too small and\nbatadv_tt_prepare_tvlv_global_data() writes past the end of the heap object\nbefore the later packet-size check runs.\n\nFix this by rejecting TT responses whose TVLV value length cannot fit in\nthe 16-bit TVLV payload length field."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"7e5d007e0df946bffb8542fb112e0044014a5897","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"2997f4bd1f982e7013709946e00be89b507693fa","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"95c71365a2222908441b54d6f2c315e0c79fcec3","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"69d61639bc7e963c3b645e570279d731e7c89062","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"f970646b9a39539d1bac86822ac78b5915455ea9","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"de6c1dc3c7d01a152607e6fcecee4d5288283f10","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"cf2199171ef799ca7270019125f4a91bd20ad4d9","versionType":"git"},{"version":"7ea7b4a142758deaf46c1af0ca9ceca6dd55138b","status":"affected","lessThan":"3a359bf5c61d52e7f09754108309d637532164a6","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/translation-table.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.13","versionType":"semver"},{"version":"5.10.253","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.203","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.169","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.135","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.82","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.23","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.13","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/translation-table.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/7e5d007e0df946bffb8542fb112e0044014a5897"},{"url":"https://git.kernel.org/stable/c/2997f4bd1f982e7013709946e00be89b507693fa"},{"url":"https://git.kernel.org/stable/c/95c71365a2222908441b54d6f2c315e0c79fcec3"},{"url":"https://git.kernel.org/stable/c/69d61639bc7e963c3b645e570279d731e7c89062"},{"url":"https://git.kernel.org/stable/c/f970646b9a39539d1bac86822ac78b5915455ea9"},{"url":"https://git.kernel.org/stable/c/de6c1dc3c7d01a152607e6fcecee4d5288283f10"},{"url":"https://git.kernel.org/stable/c/cf2199171ef799ca7270019125f4a91bd20ad4d9"},{"url":"https://git.kernel.org/stable/c/3a359bf5c61d52e7f09754108309d637532164a6"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The vulnerable path is reached by received batman-adv network packets on an active mesh hard interface via ETH_P_BATMAN/BATADV_UNICAST_TVLV into the TT TVLV handler. A malicious mesh peer can advertise a large TT and then send a TT_REQUEST that makes the victim build the oversized global TT response.\nAC:L - The trigger is a deterministic protocol sequence: create/advertise enough TT entries and send a matching request with controlled TTVN/CRC data. There is no race or condition outside attacker control once the target participates in the affected batman-adv mesh.\nPR:N - The packet receive path performs format, version, address, and active-interface checks but no authentication or privilege check for the remote sender. The attacker needs only network reachability to the batman-adv mesh, not privileges on the victim.\nUI:N - No victim user action is needed after the batman-adv interface is already active. The vulnerable response is generated automatically while processing attacker-supplied protocol packets.\nS:U - The corruption occurs inside the kernel networking subsystem and affects the same kernel security authority. This is not a VM escape, IOMMU bypass, or other cross-scope boundary violation.\nC:H - The bug is a controllable heap out-of-bounds write in kernel memory, using attacker-influenced TT entries and lengths. Such memory corruption is plausibly exploitable to obtain kernel memory disclosure primitives.\nI:H - The wrapped allocation followed by TT entry generation writes past the end of a kernel heap object. A kernel heap out-of-bounds write is a high-integrity impact because it can plausibly corrupt objects for control-flow hijack or arbitrary modification.\nA:H - The same heap corruption can reliably crash or destabilize the kernel even if not fully exploited. Repeated unauthenticated network triggering makes high availability impact defensible."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:24:11.810Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"5.10.253"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"5.15.203"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"6.1.169"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"6.6.135"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"6.12.82"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"6.18.23"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"6.19.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.13","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-31659","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:11:40.590672Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-190","lang":"en","type":"CWE","description":"CWE-190 Integer Overflow or Wraparound"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T18:56:02.093Z"}}]}}}