{"id":"CVE-2026-74321","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74321","summary":"btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()\n\nIn the beginning of the loop, we try to obtain a locked delayed ref head,\nif 'locked_ref' is currently NULL, by calling btrfs_select_ref_head(),\nwhich can return an error pointer. If the error pointer is -EAGAIN we do\na continue and go back to the beginning of the loop, which will not try\nagain to call btrfs_select_ref_head() since 'locked_ref' is no longer\nNULL but it's ERR_PTR(-EAGAIN), and then we do:\n\n   spin_lock(&locked_ref->lock);\n\nagainst a ERR_PTR(-EAGAIN) value, generating an invalid pointer\ndereference.\n\nFix this by ensuring that 'locked_ref' is set to NULL when\nbtrfs_select_ref_head() returns ERR_PTR(-EAGAIN) and incrementing 'count'\nas well, to prevent infinite looping. We do this by doing a goto to the\nbottom of the loop that already sets 'locked_ref' to NULL and does a\ncond_resched(), with an increment to 'count' right before the goto.\nThese measures were in place before the refactoring in commit 0110a4c43451\n(\"btrfs: refactor __btrfs_run_delayed_refs loop\") but were unintentionally\nlost afterwards.","published":"2026-08-15T05:58:17.485Z","modified":"2026-08-18T03:56:32.381881111Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.10.261"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/015dc4a1e0c2cba551d4620eba13d26d5081dc34"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3b15d02be05e74321adb1e0ae0cb4ccfba7c6cb1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/486f8298b6188ff11ef1f4be7f1d5d2e4d1b1fae"},{"type":"WEB","url":"https://git.kernel.org/stable/c/65770111a2d47c2b15e20b2ba92bb12198f289d4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9faa6b69ad73f03c7bde53e07d75a28822dc9a1a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a71143590ce9764dbcb47617647592ff8b4d48bc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ba9fa2ff5981589bb49094d3358c339b37c47f53"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c372ca227e16bace86f1df1fa4ae6849e2fcfa28"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74321.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74321"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:32.381881111Z"}}