{"id":"CVE-2026-64088","state":"PUBLISHED","title":"batman-adv: tt: fix negative tt_buff_len","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix negative tt_buff_len\n\nbatadv_orig_node::tt_buff_len was declared as s16, but the field is never\nintended to hold a negative value. When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_other_tt_response(), tt_buff_len is temporarily widened to\ns32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_global_data() to allocate a full sized buffer but\npopulates only a small portion of it with the collected changeset. All\nremaining bits are kept uninitialized.\n\nUsing an u16 avoids this type confusion and ensures that no (negative) sign\nextension is performed in batadv_send_other_tt_response().","publishedAt":"2026-07-19T15:39:58.084Z","updatedAt":"2026-08-05T12:39:05.060Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/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":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"4c4c2f340f4c27373bfcac8dc5032ce7bb474e47","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"33e5ede7ce6d92e531920d4bbd6d3e18ef1c6430","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"3c96dff00998314983b68a3e7caac07a66ebe496","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"32edd2a28e112064020a2f319a8cb8a9e5a09767","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"4dab98961426d0cf6a1599cda6950b7596ca2fcd","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"730de8733dd90f70d7580a9b329b971f8e1474a2","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"ed28ead3420c373a7928622f114bc6168075d1e1","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"b64963a2ceeb7529310b6cf253a1e540784422f4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/types.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.1","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.142","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.92","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","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/types.h"]}],"references":["https://git.kernel.org/stable/c/4c4c2f340f4c27373bfcac8dc5032ce7bb474e47","https://git.kernel.org/stable/c/33e5ede7ce6d92e531920d4bbd6d3e18ef1c6430","https://git.kernel.org/stable/c/3c96dff00998314983b68a3e7caac07a66ebe496","https://git.kernel.org/stable/c/32edd2a28e112064020a2f319a8cb8a9e5a09767","https://git.kernel.org/stable/c/4dab98961426d0cf6a1599cda6950b7596ca2fcd","https://git.kernel.org/stable/c/730de8733dd90f70d7580a9b329b971f8e1474a2","https://git.kernel.org/stable/c/ed28ead3420c373a7928622f114bc6168075d1e1","https://git.kernel.org/stable/c/b64963a2ceeb7529310b6cf253a1e540784422f4"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64088.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64088","state":"PUBLISHED","datePublished":"2026-07-19T15:39:58.084Z","dateUpdated":"2026-08-05T12:39:05.060Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.032Z"},"containers":{"cna":{"title":"batman-adv: tt: fix negative tt_buff_len","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix negative tt_buff_len\n\nbatadv_orig_node::tt_buff_len was declared as s16, but the field is never\nintended to hold a negative value. When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_other_tt_response(), tt_buff_len is temporarily widened to\ns32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_global_data() to allocate a full sized buffer but\npopulates only a small portion of it with the collected changeset. All\nremaining bits are kept uninitialized.\n\nUsing an u16 avoids this type confusion and ensures that no (negative) sign\nextension is performed in batadv_send_other_tt_response()."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"4c4c2f340f4c27373bfcac8dc5032ce7bb474e47","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"33e5ede7ce6d92e531920d4bbd6d3e18ef1c6430","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"3c96dff00998314983b68a3e7caac07a66ebe496","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"32edd2a28e112064020a2f319a8cb8a9e5a09767","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"4dab98961426d0cf6a1599cda6950b7596ca2fcd","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"730de8733dd90f70d7580a9b329b971f8e1474a2","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"ed28ead3420c373a7928622f114bc6168075d1e1","versionType":"git"},{"version":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7","status":"affected","lessThan":"b64963a2ceeb7529310b6cf253a1e540784422f4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/batman-adv/types.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.1","versionType":"semver"},{"version":"5.10.258","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.209","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.175","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.142","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.92","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.34","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.0.11","status":"unaffected","lessThanOrEqual":"7.0.*","versionType":"semver"},{"version":"7.1","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/types.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/4c4c2f340f4c27373bfcac8dc5032ce7bb474e47"},{"url":"https://git.kernel.org/stable/c/33e5ede7ce6d92e531920d4bbd6d3e18ef1c6430"},{"url":"https://git.kernel.org/stable/c/3c96dff00998314983b68a3e7caac07a66ebe496"},{"url":"https://git.kernel.org/stable/c/32edd2a28e112064020a2f319a8cb8a9e5a09767"},{"url":"https://git.kernel.org/stable/c/4dab98961426d0cf6a1599cda6950b7596ca2fcd"},{"url":"https://git.kernel.org/stable/c/730de8733dd90f70d7580a9b329b971f8e1474a2"},{"url":"https://git.kernel.org/stable/c/ed28ead3420c373a7928622f114bc6168075d1e1"},{"url":"https://git.kernel.org/stable/c/b64963a2ceeb7529310b6cf253a1e540784422f4"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:A - Batman-adv processes attacker-controlled translation-table TVLV traffic from mesh peers over WiFi/Ethernet L2; exploitation requires the attacker to be on the same wireless or LAN segment as the victim mesh node, matching the Adjacent definition for WiFi/L2 mesh protocols.\nAC:L - An adjacent mesh attacker can send unauthenticated TT_REQUEST/TT_RESPONSE/OGM TVLV packets to populate `tt_buff_len` and then trigger `batadv_send_other_tt_response()` without depending on victim-controlled timing or memory layout.\nPR:N - The vulnerable path is reached from pre-authentication mesh control-plane packet handling (`batadv_recv_unicast_tvlv` → `batadv_tt_tvlv_unicast_handler_v1`); no Linux credentials or capabilities are required on the victim host beyond having an active batman-adv mesh interface.\nUI:N - Exploitation requires only crafted mesh protocol packets from an adjacent attacker; no victim user action (opening files, clicking links, etc.) is needed at attack time.\nS:U - Impact is confined to kernel memory disclosure/corruption and potential local privilege escalation within the same kernel security authority; it does not cross VM, container, or IOMMU boundaries.\nC:H - Sign-extended negative `tt_buff_len` causes `batadv_tt_prepare_tvlv_global_data()` to allocate a large buffer but only partially fill it, leaving the remainder uninitialized and transmitted to the requester in the TT_RESPONSE via `batadv_tvlv_unicast_send()`.\nI:H - The same type confusion passes a negative `s16` length to `memcpy()`, which promotes to a very large `size_t` and can cause out-of-bounds reads/writes from the undersized `tt_buff` allocation, enabling heap memory corruption.\nA:H - The malformed `memcpy()` and associated heap corruption can trigger kernel oops/panic on the responding mesh node, and the bug class inherently threatens system availability even when not fully weaponized."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:39:05.060Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"5.10.258"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"5.15.209"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.1.175"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.6.142"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.12.92"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.1","versionEndExcluding":"7.1"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}