CVE-2021-47254: gfs2: Fix use-after-free in gfs2_glock_shrink_scan
Vulnerability summary
CVE-2021-47254 is a high (CVSS 7.8) Use After Free vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 15.5% of scored vulnerabilities.
Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 8 · Related 8Timeline
- 21-05-2024PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
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 metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
16%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.24% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu86 products
- linux< 4.4.0-279.313 | < 4.15.0-156.163 | < 5.4.0-81.91
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 4.4.0-1153.159 | < 4.4.0-1191.206 | < 4.15.0-1111.118 | < 5.4.0-1055.58
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 6948c6bc17d666663a84c124b3176039e64a58f4, < 38ce329534500bf4ae71f81df6a37a406cf187b4 | ≥ b568ed385a18c0ddbe41862b69088b636550a04f, < 92869945cc5b78ee8a1ef90336fe070893e3458a | ≥ 762bb3528249604bc680a9df635e8995740176de, < 0364742decb0f02bc183404868b82896f7992595 | ≥ bac8520892812dada1ac93f27d96317470d24b1f, < 094bf5670e762afa243d2c41a5c4ab71c7447bf4 | ≥ 7881ef3f33bb80f459ea6020d1e021fc524a6348, < 86fd5b27db743a0ce0cc245e3a34813b2aa6ec1d | ≥ 7881ef3f33bb80f459ea6020d1e021fc524a6348, < a61156314b66456ab6a291ed5deba1ebd002ab3c | ≥ 7881ef3f33bb80f459ea6020d1e021fc524a6348, < e87ef30fe73e7e10d2c85bdcc778dcec24dca553 | ≥ 7881ef3f33bb80f459ea6020d1e021fc524a6348, < 1ab19c5de4c537ec0d9b21020395a5b5a6c059b2 | 1e7a416fb765c9072479dc424780c0937ba99270 | dcbdbe13796ffa561510d2686a6318564e728bbd | ≥ 4.4.181, < 4.4.274 | ≥ 4.9.180, < 4.9.274 | ≥ 4.14.123, < 4.14.238 | ≥ 4.19.47, < 4.19.196 | ≥ 5.0.20, < 5.1 | ≥ 5.1.6, < 5.2 | 5.2
- linux_kernel≥ 4.4.181, < 4.4.274 | ≥ 4.9.180, < 4.9.274 | ≥ 4.14.123, < 4.14.238 | ≥ 4.19.47, < 4.19.196 | ≥ 5.0.20, < 5.1 | ≥ 5.1.6, < 5.4.127 | ≥ 5.5, < 5.10.45 | ≥ 5.11, < 5.12.12 | 5.13:rc1 | 5.13:rc2 | 5.13:rc3 | 5.13:rc4
Debian1 product
- linux< 5.10.46-1
3 vendors · 89 products
