Affected: AlmaLinux:10: glibc, AlmaLinux:10: glibc-all-langpacks, AlmaLinux:10: glibc-benchtests, AlmaLinux:10: glibc-common, AlmaLinux:10: glibc-devel, AlmaLinux:10: glibc-doc, AlmaLinux:10: glibc-gconv-extra, AlmaLinux:10: glibc-langpack-aa, AlmaLinux:10: glibc-langpack-af, AlmaLinux:10: glibc-langpack-agr and 211 more

The glibc packages provide the standard C libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the name service cache daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.

Security Fix(es):

* glibc: glibc: Information disclosure or denial of service via ungetwc function with specific wide character encodings (CVE-2026-5928) * glibc: glibc: Out-of-bounds write via TSIG record processing (CVE-2026-5435) * glibc: glibc: Application crash or uninitialized memory read via crafted DNS response (CVE-2026-6238)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Affected: Homebrew: glibc

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.

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.

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.

Affected: openEuler:20.03-LTS-SP4: glibc

The GNU C Library project provides the core libraries for the GNU system and GNU/Linux systems, as well as many other systems that use Linux as the kernel. These libraries provide critical APIs including ISO C11, POSIX.1-2008, BSD, OS-specific APIs and more. These APIs include such foundational facilities as open, read, write, malloc, printf, getaddrinfo, dlopen, pthread_create, crypt, login, exit and more. Security Fix(es):

Calling the scanf family of functions with a %mc (malloc'd character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow.(CVE-2026-5450)

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 speci…

glibc-2.43-3.1 on GA media

glibc: glibc: Denial of Service via iconv() function with specific character sets glibc: glibc: Out-of-bounds write via TSIG record processing glibc: glibc: Heap Buffer Overflow in `scanf` with `%mc` format specifier and large width glibc: glibc: Information disclosure or denial of service via ungetwc function with specific wide character encodings glibc: glibc: Application crash or uninitialized memory read via crafted DNS response

Affected: Rocky Linux:10: glibc

The glibc packages provide the standard C libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the name service cache daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.

Security Fix(es):

* glibc: glibc: Information disclosure or denial of service via ungetwc function with specific wide character encodings (CVE-2026-5928)

* glibc: glibc: Out-of-bounds write via TSIG record processing (CVE-2026-5435)

* glibc: glibc: Application crash or uninitialized memory read via crafted DNS response (CVE-2026-6238)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Multiple vulnerabilities have been identified in the additional GNU/Linux subsystem of the firmware version V3.1.5 for the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP (incl. SIPLUS variant).

Siemens has released new versions for several affected products and recommends to update to the latest versions. Siemens is preparing further fix versions and recommends specific countermeasures for products where fixes are not, or not yet available.

Note: This SSA advises vulnerabilities for firmware version V3.1.5 only; for version V3.1.6 refer to SSA-019113.

Security update for glibc

Affected: Ubuntu:Pro:14.04:LTS: eglibc, Ubuntu:Pro:16.04:LTS: glibc, Ubuntu:Pro:18.04:LTS: glibc, Ubuntu:Pro:20.04:LTS: glibc, Ubuntu:22.04:LTS: glibc, Ubuntu:24.04:LTS: glibc, Ubuntu:25.10: glibc, Ubuntu:26.04:LTS: glibc

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.

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in GNU libc ausnutzen, um Dateien zu manipulieren, einen Denial-of-Service-Zustand zu verursachen oder andere, nicht näher spezifizierte Angriffe durchzuführen.