{"api_version":"1","generated_at":"2026-07-22T12:31:44+00:00","cve":"CVE-2026-64089","urls":{"html":"https://cve.report/CVE-2026-64089","api":"https://cve.report/api/cve/CVE-2026-64089.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64089","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64089"},"summary":{"title":"batman-adv: tt: fix negative last_changeset_len","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix negative last_changeset_len\n\nbatadv_piv_tt::last_changeset_len len was declared as s16, but the field is\nnever intended to hold a negative value. When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_my_tt_response(), last_changeset_len is temporarily widened\nto s32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_local_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_my_tt_response().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:49","updated_at":"2026-07-20 15:17:08"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"9.8","severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":9.8,"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"}}],"references":[{"url":"https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b","name":"https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15","name":"https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c","name":"https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8","name":"https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52","name":"https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4","name":"https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14","name":"https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee","name":"https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64089","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64089","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a73105b8d4c765d9ebfb664d0a66802127d8e4c7 6314089acf0ddf64376fdc0b1420695504c73f52 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a73105b8d4c765d9ebfb664d0a66802127d8e4c7 55dc41fe8821e9a849e147255ad572bc933a9d15 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a73105b8d4c765d9ebfb664d0a66802127d8e4c7 c424e8519ac78eac5d9f4eecf06208a0d619ec14 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a73105b8d4c765d9ebfb664d0a66802127d8e4c7 22d59c72f4a47ffec121d0610f70d0d70c3c11c8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64089","cve":"CVE-2026-64089","epss":"0.001840000","percentile":"0.082510000","score_date":"2026-07-20","updated_at":"2026-07-21 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the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix negative last_changeset_len\n\nbatadv_piv_tt::last_changeset_len len was declared as s16, but the field is\nnever intended to hold a negative value. When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_my_tt_response(), last_changeset_len is temporarily widened\nto s32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_local_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_my_tt_response()."}],"metrics":[{"cvssV3_1":{"baseScore":9.8,"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"}}],"providerMetadata":{"dateUpdated":"2026-07-20T13:43:12.374Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52"},{"url":"https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15"},{"url":"https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14"},{"url":"https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8"},{"url":"https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b"},{"url":"https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c"},{"url":"https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee"},{"url":"https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4"}],"title":"batman-adv: tt: fix negative last_changeset_len","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64089","datePublished":"2026-07-19T15:39:58.729Z","dateReserved":"2026-07-19T07:54:57.032Z","dateUpdated":"2026-07-20T13:43:12.374Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:49","lastModifiedDate":"2026-07-20 15:17:08","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64089","Ordinal":"1","Title":"batman-adv: tt: fix negative last_changeset_len","CVE":"CVE-2026-64089","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64089","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: tt: fix negative last_changeset_len\n\nbatadv_piv_tt::last_changeset_len len was declared as s16, but the field is\nnever intended to hold a negative value. When a value greater than 32767 is\nassigned, it wraps to a negative signed integer.\n\nIn batadv_send_my_tt_response(), last_changeset_len is temporarily widened\nto s32. The incorrectly negative s16 value propagates into the s32, causing\nbatadv_tt_prepare_tvlv_local_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_my_tt_response().","Type":"Description","Title":"batman-adv: tt: fix negative last_changeset_len"}]}}}