CVE-2025-21945: linux Use After Free
CVSS: 8.8v3.1HighModified
AliasesUBUNTU-CVE-2025-21945DEBIAN-CVE-2025-21945
Published 01-04-2025Last modified 05-08-2026
Vulnerability summary
CVE-2025-21945 is a high (CVSS 8.8) Use After Free vulnerability in linux. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 42.6% of scored vulnerabilities.
CVSS score
8.8/10
010
High · v3.1 (CVE.org)EPSS score
0.52%
0%100%
Low · +0.01 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 20 · Related 18Timeline
- 01-04-2025PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in smb2_lock If smb_lock->zero_len has value, ->llist of smb_lock is not delete and flock is old one. It will cause use-after-free on error handling routine.
CVSS metrics
5 scores · 4 sources · 2 versionsHigh 8.7Preferred score · OSV · Ubuntu (Ecosystem advisory) · calculated from vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NSourcesSingle source
High 8.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSources4 sources · 7.8–8.8
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/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:HDiffers
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HDiffers
EPSS trend
Probability
0.52%
Chance of exploitation in the next 30 days
Percentile
43%
Versus all other CVEs
30-day change
+0.01 pp
From 0.51% on 19-09-2026
19-09-202619-10-2026
EPSS score0.52%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu126 products
- linuxAll versions (No fix recorded) | < 6.8.0-84.84
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 6.8.0-1039.41
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 410ce35a2ed6d0e114132bba29af49b69880c8c7 | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 8573571060ca466cbef2c6f03306b2cc7b883506 | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < a0609097fd10d618aed4864038393dd75131289e | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 636e021646cf9b52ddfea7c809b018e91f2188cb | ≥ 0626e6641f6b467447c81dd7678a69c66f7746cf, < 84d2d1641b71dec326e8736a749b7ee76a9599fc | 5.15
- linux_kernel≥ 5.15, < 6.1.131 | ≥ 6.2, < 6.6.83 | ≥ 6.7, < 6.12.19 | ≥ 6.13, < 6.13.7 | 6.14:rc1 | 6.14:rc2 | 6.14:rc3 | 6.14:rc4 | 6.14:rc5
Debian1 product
- linux< 6.1.133-1 | < 6.12.19-1
3 vendors · 129 products
