Skip to content
Fencer Intel
medium 4.2

CVE-2026-125709 json

Libstdc++: overflow leaves streambuf in inconsistent state on i/o error.

published yesterday modified yesterday also EUVD-2026-120884

cvss
4.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 10%
public exploits
0
none known

Summary

A flaw was found in libstdc++. When a byte-by-byte write operation fails during file stream processing, the library may still append data into the internal memory buffer. An attacker capable of inducing repeated write failures in an affected service can trigger a buffer overflow, potentially resulting in a Denial of Service (DoS) or memory corruption.

Is CVE-2026-125709 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-125709 updated cvss 4.2

libstdc++: overflow leaves streambuf in inconsistent state on I/O error.

  • Red Hat Enterprise Linux 6 cpp, gcc, libgcc, libgcj, libitm, gcc-c++, +23 more Red Hat Enterprise Linux 7 cpp, gcc, libgo, gcc-go, libgcc, libitm, +20 more Red Hat Enterprise Linux 8 cpp, gcc, libgcc, libitm, gcc-c++, libasan, +27 more Red Hat Enterprise Linux 9 cpp, gcc, libgcc, libitm, gcc-c++, libasan, +39 more Red Hat Enterprise Linux 10 gcc, mingw-gcc, mingw32-gcc, mingw64-gcc, gcc-toolset-15-gcc, gcc-toolset-16-gcc
    affected: no fix available “Fix deferred”
  • Red Hat Hardened Images gcc, gcc13 13.5.0-0.5.hum1
    affected: no fix available
  • Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
yesterday

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:L

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Hardened Images
  • Red Hat Red Hat OpenShift Container Platform 4
  • Red Hat Red Hat OpenShift Container Platform 5

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.