SB2026100231 - Buffer under-read in GNU C Library

Description

This security bulletin contains information about 1 vulnerability.

1) Buffer under-read (CVE-ID: CVE-2026-5928)

CWE-ID: CWE-127 - Buffer Under-read

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to perform a denial of service attack.

The vulnerability exists due to calling the ungetwc function on a FILE stream with wide characters encoded in a character set that has overlaps between its single byte and multi-byte character encodings, in the GNU C Library may result in an attempt to read bytes before an allocated buffer. A remote attacker can pass specially crafted data to the application, causing disclosure of neighboring data in the heap, or a program crash.

Remediation

Install update from vendor's website.

References

• https://sourceware.org/bugzilla/show_bug.cgi?id=33998
• https://cert-portal.siemens.com/productcert/html/ssa-082556.html