CVE-2026-74321

CVE CVE-2026-74321EUVD EUVD-2026-59468Published 2026-08-15T05:58:17.000ZLast changed 2026-08-17T05:45:52.000ZCVSS 7.5

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs() In the beginning of the loop, we try to obtain a locked delayed ref head, if 'locked_ref' is currently NULL, by calling btrfs_select_ref_head(), which can return an error pointer. If the error pointer is -EAGAIN we do a continue and go back to the beginning of the loop, which will not try again to call btrfs_select_ref_head() since 'locked_ref' is no longer NULL but it's ERR_PTR(-EAGAIN), and then we do: spin_lock(&locked_ref->lock); against a ERR_PTR(-EAGAIN) value, generating an invalid pointer dereference. Fix this by ensuring that 'locked_ref' is set to NULL when btrfs_select_ref_head() returns ERR_PTR(-EAGAIN) and incrementing 'count' as well, to prevent infinite looping. We do this by doing a goto to the bottom of the loop that already sets 'locked_ref' to NULL and does a cond_resched(), with an increment to 'count' right before the goto. These measures were in place before the refactoring in commit 0110a4c43451 ("btrfs: refactor __btrfs_run_delayed_refs loop") but were unintentionally lost afterwards.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux patch: 6.12.97; patch: 6.1.178; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <65770111a2d47c2b15e20b2ba92bb12198f289d4; patch: 6.6.145; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <a71143590ce9764dbcb47617647592ff8b4d48bc; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <9faa6b69ad73f03c7bde53e07d75a28822dc9a1a; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <3b15d02be05e74321adb1e0ae0cb4ccfba7c6cb1; patch: 7.1.5; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <c372ca227e16bace86f1df1fa4ae6849e2fcfa28; patch: 5.15.212; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <ba9fa2ff5981589bb49094d3358c339b37c47f53; patch: 6.18.40; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <015dc4a1e0c2cba551d4620eba13d26d5081dc34; patch: 0; 0110a4c43451533de1ea1bbdc57b5d452f9d8b25 <486f8298b6188ff11ef1f4be7f1d5d2e4d1b1fae; 4.20; patch: 5.10.261; patch: 7.2

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Carried in the product catalogue

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Linux — Linux

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