PT-2026-33852 · Gnu · Gnu C Library
Rocket Ma
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Published
2026-04-20
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Updated
2026-06-10
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CVE-2026-5928
CVSS v3.1
7.5
High
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
gnu C Library versions prior to 2.44
Description
Calling the ungetwc function on a FILE stream with wide characters encoded in a character set with overlaps between single byte and multi-byte character encodings can lead to an attempt to read bytes before an allocated buffer. This occurs due to a bug in the wide character pushback implementation
IO wdefault pbackfail() in libio/wgenops.c, which causes ungetwc() to use the regular character buffer fp-> IO read ptr instead of the wide-stream read pointer fp-> wide data-> IO read ptr. This may result in a program crash if fp-> IO read ptr is NULL or the unintentional disclosure of neighboring data in the heap. This issue requires a specific character encoding where single byte and multibyte representations overlap, creating spurious matches, a condition not present in standard Unicode character sets.Recommendations
Update to a version newer than 2.43.
Exploit
Fix
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Weakness Enumeration
Related Identifiers
Affected Products
Gnu C Library