4.9

CVE-2026-18374: the gnu c library glibc Out-of-bounds Write

CVSS: 4.9v3.1MediumAwaiting analysis
AliasesRHSA-2026:65339UBUNTU-CVE-2026-18374DEBIAN-CVE-2026-18374
Published 27-08-2026Last modified 28-08-2026
Open JSON

Vulnerability summary

CVE-2026-18374 is a medium (CVSS 4.9) Out-of-bounds Write vulnerability in the gnu c library glibc. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 3.3% of scored vulnerabilities.

Overall risk
20/100
0100
Low · default modelHow is this calculated?
CVSS score
4.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.14%
0%100%
Low · -0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 13 · Related 10
OPENSUSE-SU-2026:11787-1OPENSUSE-SU-2026:21968-1RHSA-2026:79281RHSA-2026:80798RHSA-2026:84753SUSE-SU-2026:23738-1

Timeline

  1. 27-08-2026
    PublishedVulnerability first disclosed.
  2. 28-08-2026
    Last modifiedVulnerability information updated.

Description

Passing an effectively empty string to the `,ccs=` syntax extension of the mode argument in the `fopen` function in the GNU C Library version 2.45 or earlier may result in a heap buffer overflow when the mode string input to the function is attacker controlled. This usage pattern is not seen in applications in common GNU/Linux distributions and applications that process user-supplied values for `ccs` should not pass them through without validation.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.14%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

-0.01 pp

From 0.15% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.14%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Redhat89 products
  • compat-libpthread-nonshared< 0:2.43-8.5.hum1
  • glibc< 0:2.43-8.5.hum1
  • glibc-all-langpacks< 0:2.43-8.5.hum1
  • glibc-benchtests< 0:2.43-8.5.hum1
  • glibc-common< 0:2.43-8.5.hum1
Chainguard54 products
  • glibc-2.43All versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-abi-reportAll versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-devAll versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-iconvAll versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-locale-caAll versions (No fix recorded) | < 2.43-r18
Wolfi54 products
  • glibc-2.43All versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-abi-reportAll versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-devAll versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-iconvAll versions (No fix recorded) | < 2.43-r18
  • glibc-2.43-locale-caAll versions (No fix recorded) | < 2.43-r18
Ubuntu2 products
  • eglibcAll versions (No fix recorded)
  • glibcAll versions (No fix recorded)
Debian1 product
  • glibcAll versions (No fix recorded) | < 2.43-5

5 vendors · 200 products · Showing 200 of 340. Use Open JSON for the complete list.

References

14 links
Show all 14 references