CVE-2025-21853: linux
Vulnerability summary
CVE-2025-21853 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.1% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 36 · Related 30Timeline
- 12-03-2025PublishedVulnerability first disclosed.
- 15-10-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: avoid holding freeze_mutex during mmap operation We use map->freeze_mutex to prevent races between map_freeze() and memory mapping BPF map contents with writable permissions. The way we naively do this means we'll hold freeze_mutex for entire duration of all the mm and VMA manipulations, which is completely unnecessary. This can potentially also lead to deadlocks, as reported by syzbot in [0]. So, instead, hold freeze_mutex only during writeability checks, bump (proactively) "write active" count for the map, unlock the mutex and proceed with mmap logic. And only if something went wrong during mmap logic, then undo that "write active" counter increment. [0] https://lore.kernel.org/bpf/678dcbc9.050a0220.303755.0066.GAE@google.com/
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.25%
Chance of exploitation in the next 30 days
Percentile
15%
Versus all other CVEs
30-day change
0.00 pp
From 0.24% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu125 products
- linux< 5.15.0-144.157 | < 6.8.0-78.78
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 5.15.0-1088.95 | < 6.8.0-1035.37
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ fc9702273e2edb90400a34b3be76f7b08fa3344b, < 2ce31c97c219b4fe797749f950274f246eb88c49 | ≥ fc9702273e2edb90400a34b3be76f7b08fa3344b, < 0d90d9e154144a3a80e9fc0eb9b21b7fc990f68f | ≥ fc9702273e2edb90400a34b3be76f7b08fa3344b, < 4759acbd44d24a69b7b14848012ec4201d6c5501 | ≥ fc9702273e2edb90400a34b3be76f7b08fa3344b, < 29cfda62ab4d92ab94123813db49ab76c1e61b29 | ≥ fc9702273e2edb90400a34b3be76f7b08fa3344b, < d95607a5f2f9bb08194c9deaf4a5f3e8ba59a9d4 | ≥ fc9702273e2edb90400a34b3be76f7b08fa3344b, < 271e49f8a58edba65bc2b1250a0abaa98c4bfdbe | ≥ fc9702273e2edb90400a34b3be76f7b08fa3344b, < bc27c52eea189e8f7492d40739b7746d67b65beb | 5.5
- linux_kernel≥ 5.5, < 6.6.80 | ≥ 6.7, < 6.12.17 | ≥ 6.13, < 6.13.5 | 6.14:rc1 | 6.14:rc2 | 6.14:rc3
Debian1 product
- linux< 6.1.135-1 | < 6.12.17-1
3 vendors · 128 products
