{"id":"CVE-2026-64089","summary":"batman-adv: tt: fix negative last_changeset_len","details":"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().","modified":"2026-07-22T03:31:36.615566862Z","published":"2026-07-19T15:39:58.729Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64089.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/179eb62506a02d00370bd6478898cb632e10986c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/22d59c72f4a47ffec121d0610f70d0d70c3c11c8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/55dc41fe8821e9a849e147255ad572bc933a9d15"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6314089acf0ddf64376fdc0b1420695504c73f52"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c424e8519ac78eac5d9f4eecf06208a0d619ec14"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d29abf70c665730e249d2ec8e1402095ae26bcee"},{"type":"WEB","url":"https://git.kernel.org/stable/c/eb235472b52ef36981c5aad330485eaf2382c53b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fc92cdfcb295cefa4344d71a527d61b638b7bfc4"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64089.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64089"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a73105b8d4c765d9ebfb664d0a66802127d8e4c7"},{"fixed":"6314089acf0ddf64376fdc0b1420695504c73f52"},{"fixed":"55dc41fe8821e9a849e147255ad572bc933a9d15"},{"fixed":"c424e8519ac78eac5d9f4eecf06208a0d619ec14"},{"fixed":"22d59c72f4a47ffec121d0610f70d0d70c3c11c8"},{"fixed":"eb235472b52ef36981c5aad330485eaf2382c53b"},{"fixed":"179eb62506a02d00370bd6478898cb632e10986c"},{"fixed":"d29abf70c665730e249d2ec8e1402095ae26bcee"},{"fixed":"fc92cdfcb295cefa4344d71a527d61b638b7bfc4"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-64089.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.1.0"},{"fixed":"5.10.258"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.209"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.175"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.142"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.92"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.34"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.0.11"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-64089.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}