{"id":"CVE-2026-64095","summary":"batman-adv: bla: avoid double decrement of bla.num_requests","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbatman-adv: bla: avoid double decrement of bla.num_requests\n\nThe bla.num_requests is increased when no request_sent was in progress. And\nit is decremented in various places (announcement was received, backbone is\npurged, periodic work). But the check if the request_sent is actually set\nto a specific state and the atomic_dec/_inc are not safe because they are\nnot atomic (TOCTOU) and multiple such code portions can run concurrently.\n\nAt the same time, it is necessary to modify request_sent (state) and\nbla.num_requests atomically. Otherwise batadv_bla_send_request() might set\nrequest_sent to 1 and is interrupted.  batadv_handle_announce() can then\nset request_sent back to 0 and decrement num_requests before\nbatadv_bla_send_request() incremented it.\n\nThe two operations must therefore be locked. And since state (request_sent)\nand wait_periods are only accessed inside this lock, they can be converted\nto simpler datatypes. And to avoid that the bla.num_requests is touched by\na parallel running context with a valid backbone_gw reference after\nbatadv_bla_purge_backbone_gw() ran, a third state \"stopped\" is required to\ncorrectly signal that a backbone_gw is in the state of being cleaned up.","modified":"2026-07-22T03:32:10.544310766Z","published":"2026-07-19T15:40:02.360Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64095.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1f013bc94154f2e78e97d0296175664224c796e0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/45384612f29692fbf0c770200361a7acff90125c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/461f1e3dfb888701895b766446c55db2b10db705"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5328b95960774f2e189f22485616bc7b8eb2f7e3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/65497ad155a3246df177b5ef662cd6e5a32cb470"},{"type":"WEB","url":"https://git.kernel.org/stable/c/83ab69bd12b80f6ea169c8bea6977701b53a043d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8ff9c59d1b7b48c2596878341a5310f32895d52b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a9393751ecf7e9096f93cb6eed02db4f79125765"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64095.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64095"},{"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":"23721387c409087fd3b97e274f34d3ddc0970b74"},{"fixed":"1f013bc94154f2e78e97d0296175664224c796e0"},{"fixed":"5328b95960774f2e189f22485616bc7b8eb2f7e3"},{"fixed":"8ff9c59d1b7b48c2596878341a5310f32895d52b"},{"fixed":"a9393751ecf7e9096f93cb6eed02db4f79125765"},{"fixed":"461f1e3dfb888701895b766446c55db2b10db705"},{"fixed":"45384612f29692fbf0c770200361a7acff90125c"},{"fixed":"65497ad155a3246df177b5ef662cd6e5a32cb470"},{"fixed":"83ab69bd12b80f6ea169c8bea6977701b53a043d"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-64095.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.5.0"},{"fixed":"5.10.259"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.210"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.176"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.143"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.93"}]},{"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-2026-64095.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H"}]}