CVE-2026-5928 Affecting glibc-static package, versions <0:2.34-274.0.1.el9_8


Severity

Recommended
medium

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.37% (30th percentile)

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  • Snyk IDSNYK-ORACLE9-GLIBCSTATIC-18278467
  • published23 Jul 2026
  • disclosed20 Apr 2026

Introduced: 20 Apr 2026

CVE-2026-5928  (opens in a new tab)

How to fix?

Upgrade Oracle:9 glibc-static to version 0:2.34-274.0.1.el9_8 or higher.
This issue was patched in ELSA-2026-42952.

NVD Description

Note: Versions mentioned in the description apply only to the upstream glibc-static package and not the glibc-static package as distributed by Oracle. See How to fix? for Oracle:9 relevant fixed versions and status.

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 version 2.43 or earlier, may result in an attempt to read bytes before an allocated buffer, potentially resulting in unintentional disclosure of neighboring data in the heap, or a program crash.

A bug in the wide character pushback implementation (_IO_wdefault_pbackfail in libio/wgenops.c) causes ungetwc() to operate on the regular character buffer (fp->_IO_read_ptr) instead of the actual wide-stream read pointer (fp->_wide_data->_IO_read_ptr). The program crash may happen in cases where fp->_IO_read_ptr is not initialized and hence points to NULL. The buffer under-read requires a special situation where the input character encoding is such that there are overlaps between single byte representations and multibyte representations in that encoding, resulting in spurious matches. The spurious match case is not possible in the standard Unicode character sets.

CVSS Base Scores

version 3.1