CVE-2024-50273: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.3% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: btrfs: reinitialize delayed ref list after deleting it from the list At insert_delayed_ref() if we need to update the action of an existing ref to BTRFS_DROP_DELAYED_REF, we delete the ref from its ref head's ref_add_list using list_del(), which leaves the ref's add_list member not reinitialized, as list_del() sets the next and prev members of the list to LIST_POISON1 and LIST_POISON2, respectively. If later we end up calling drop_delayed_ref() against the ref, which can happen during merging or when destroying delayed refs due to a transaction abort, we can trigger a crash since at drop_delayed_ref() we call list_empty() against the ref's add_list, which returns false since the list was not reinitialized after the list_del() and as a consequence we call list_del() again at drop_delayed_ref(). This results in an invalid list access since the next and prev members are set to poison pointers, resulting in a splat if CONFIG_LIST_HARDENED and CONFIG_DEBUG_LIST are set or invalid poison pointer dereferences otherwise. So fix this by deleting from the list with list_del_init() instead.

Affected products

• Linux Linux Kernel: from 4.10, before 4.19.324 (fixed in 4.19.324); from 4.20, before 5.4.286 (fixed in 5.4.286); from 5.5, before 5.10.230 (fixed in 5.10.230); from 5.11, before 5.15.172 (fixed in 5.15.172); from 5.16, before 6.1.117 (fixed in 6.1.117); from 6.2, before 6.6.61 (fixed in 6.6.61); …

Published 2024-11-19. Last modified 2026-08-04.