CVE-2021-47254
In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in gfs2_glock_shrink_scan The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to remove the glock from the lru list in __gfs2_glock_put().
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.24%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in gfs2_glock_shrink_scan The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to remove the glock from the lru list in __gfs2_glock_put(). On the shrink scan path, the same flag is cleared under lru_lock but because of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the put side can be made without deleting the glock from the lru list. Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to ensure correct behavior on both sides - clear GLF_LRU after list_del under lru_lock.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.24% probability · 15th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595Patch
- https://git.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4Patch
- https://git.kernel.org/stable/c/1ab19c5de4c537ec0d9b21020395a5b5a6c059b2Patch
- https://git.kernel.org/stable/c/38ce329534500bf4ae71f81df6a37a406cf187b4Patch
- https://git.kernel.org/stable/c/86fd5b27db743a0ce0cc245e3a34813b2aa6ec1dPatch
- https://git.kernel.org/stable/c/92869945cc5b78ee8a1ef90336fe070893e3458aPatch
- https://git.kernel.org/stable/c/a61156314b66456ab6a291ed5deba1ebd002ab3cPatch
- https://git.kernel.org/stable/c/e87ef30fe73e7e10d2c85bdcc778dcec24dca553Patch
- https://git.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595Patch
- https://git.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4Patch
- https://git.kernel.org/stable/c/1ab19c5de4c537ec0d9b21020395a5b5a6c059b2Patch
- https://git.kernel.org/stable/c/38ce329534500bf4ae71f81df6a37a406cf187b4Patch
- https://git.kernel.org/stable/c/86fd5b27db743a0ce0cc245e3a34813b2aa6ec1dPatch
- https://git.kernel.org/stable/c/92869945cc5b78ee8a1ef90336fe070893e3458aPatch
- https://git.kernel.org/stable/c/a61156314b66456ab6a291ed5deba1ebd002ab3cPatch
- https://git.kernel.org/stable/c/e87ef30fe73e7e10d2c85bdcc778dcec24dca553Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.