5.5

CVE-2025-21963: cifs: Fix integer overflow while processing acdirmax mount option

Modified
AliasesUBUNTU-CVE-2025-21963DEBIAN-CVE-2025-21963
Published 01-04-2025Last modified 11-05-2026

Vulnerability summary

CVE-2025-21963 is a medium (CVSS 5.5) Integer Overflow or Wraparound vulnerability in linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.21%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 49 · Related 43
DLA-4193-1DSA-5900-1MGASA-2025-0142MGASA-2025-0146RHSA-2025:9079RHSA-2025:9080

Timeline

  1. 01-04-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: cifs: Fix integer overflow while processing acdirmax mount option User-provided mount parameter acdirmax of type u32 is intended to have an upper limit, but before it is validated, the value is converted from seconds to jiffies which can lead to an integer overflow. Found by Linux Verification Center (linuxtesting.org) with SVACE.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

11%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.20% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu125 products
  • linux< 5.15.0-142.152 | < 6.8.0-84.84
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 5.15.0-1086.93 | < 6.8.0-1039.41
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 4c9f948142a550af416a2bfb5e56d29ce29e92cf, < 0c26edf477e093cefc41637f5bccc102e1a77399 | ≥ 4c9f948142a550af416a2bfb5e56d29ce29e92cf, < 39d086bb3558da9640ef335f97453e01d32578a1 | ≥ 4c9f948142a550af416a2bfb5e56d29ce29e92cf, < 9e438d0410a4002d24f420f2c28897ba2dc0af64 | ≥ 4c9f948142a550af416a2bfb5e56d29ce29e92cf, < 2809a79bc64964ce02e0c5f2d6bd39b9d09bdb3c | ≥ 4c9f948142a550af416a2bfb5e56d29ce29e92cf, < 6124cbf73e3dea7591857dd63b8ccece28952afd | ≥ 4c9f948142a550af416a2bfb5e56d29ce29e92cf, < 5b29891f91dfb8758baf1e2217bef4b16b2b165b | 5.12
  • linux_kernel≥ 5.12, < 5.15.180 | ≥ 5.16, < 6.1.132 | ≥ 6.2, < 6.6.84 | ≥ 6.7, < 6.12.20 | ≥ 6.13, < 6.13.8 | 6.14:rc1 | 6.14:rc2 | 6.14:rc3 | 6.14:rc4 | 6.14:rc5 | 6.14:rc6
Debian1 product
  • linux< 6.1.133-1 | < 6.12.20-1

3 vendors · 128 products

References

43 links
Show all 43 references