CVE-2021-47254
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-416 · Use after free
- Record status
- Modified
Affected
- Linux Kernel < 4.4.274
- Linux Kernel < 4.9.274
- Linux Kernel < 4.14.238
- Linux Kernel < 4.19.196
- Linux Kernel < 5.1
- Linux Kernel < 5.4.127
- Linux Kernel < 5.10.45
- Linux Kernel < 5.12.12
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-47254.md and follow it. Check whether this project is affected by CVE-2021-47254. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595
- https://git.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4
- https://git.kernel.org/stable/c/1ab19c5de4c537ec0d9b21020395a5b5a6c059b2
- https://git.kernel.org/stable/c/38ce329534500bf4ae71f81df6a37a406cf187b4
- https://git.kernel.org/stable/c/86fd5b27db743a0ce0cc245e3a34813b2aa6ec1d
- https://git.kernel.org/stable/c/92869945cc5b78ee8a1ef90336fe070893e3458a
- https://git.kernel.org/stable/c/a61156314b66456ab6a291ed5deba1ebd002ab3c
- https://git.kernel.org/stable/c/e87ef30fe73e7e10d2c85bdcc778dcec24dca553
- https://git.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595
- https://git.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4
References
- https://git.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595
- https://git.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4
- https://git.kernel.org/stable/c/1ab19c5de4c537ec0d9b21020395a5b5a6c059b2
- https://git.kernel.org/stable/c/38ce329534500bf4ae71f81df6a37a406cf187b4
- https://git.kernel.org/stable/c/86fd5b27db743a0ce0cc245e3a34813b2aa6ec1d
- https://git.kernel.org/stable/c/92869945cc5b78ee8a1ef90336fe070893e3458a
- https://git.kernel.org/stable/c/a61156314b66456ab6a291ed5deba1ebd002ab3c
- https://git.kernel.org/stable/c/e87ef30fe73e7e10d2c85bdcc778dcec24dca553
- https://git.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595
- https://git.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4
- https://git.kernel.org/stable/c/1ab19c5de4c537ec0d9b21020395a5b5a6c059b2
- https://git.kernel.org/stable/c/38ce329534500bf4ae71f81df6a37a406cf187b4
- https://git.kernel.org/stable/c/86fd5b27db743a0ce0cc245e3a34813b2aa6ec1d
- https://git.kernel.org/stable/c/92869945cc5b78ee8a1ef90336fe070893e3458a
- https://git.kernel.org/stable/c/a61156314b66456ab6a291ed5deba1ebd002ab3c
- https://git.kernel.org/stable/c/e87ef30fe73e7e10d2c85bdcc778dcec24dca553