CVE-2026-5450

Converting crafted EUC_JISX0213 input to UCS-4 or the internal wide character encoding, for example with iconv, in the GNU C Library version 2.3 to 2.44 may result in the converter making no progress, causing the calling application to hang. Some EUC_JISX0213 sequences decode to two code points. If the output buffer has room for only the first one, the converter stores the second in the conversion state and returns E2BIG, but it never clears that pending character after emitting it on the next call. The converter then keeps emitting the pending character without consuming further input, so an application that retries the conversion loops forever. The input must be attacker controlled and the application must convert it with an output buffer small enough to split the two code points. Only the EUC_JISX0213 character set is affected, which is not commonly used.

Converting crafted SHIFT_JISX0213 input to UCS-4 or the internal wide character encoding, for example with iconv, in the GNU C Library version 2.3 to 2.44 may result in the converter making no progress, causing the calling application to hang. Some SHIFT_JISX0213 sequences decode to two code points. If the output buffer has room for only the first one, the converter stores the second in the conversion state and returns E2BIG, but it never clears that pending character after emitting it on the next call. The converter then keeps emitting the pending character without consuming further input, so an application that retries the conversion loops forever. The input must be attacker controlled and the application must convert it with an output buffer small enough to split the two code points. Only the SHIFT_JISX0213 character set is affected, which is not commonly used.

The iconv() function in the GNU C Library versions 2.39 and older may overflow the output buffer by up to 4 bytes when converting strings to the ISO-2022-CN-EXT character set. This may lead to application crashes or overwrite a neighbouring variable.

A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.

In GNU C Library versions 2.27 to 2.38, an untrusted LD_LIBRARY_PATH environment variable vulnerability allows attacker-controlled loading of dynamically shared libraries in statically compiled setuid binaries that call dlopen (including internal dlopen calls after setlocale or calls to NSS functions).

In GNU C Library versions 2.13 to 2.40, when the assert() function fails, it does not allocate enough space for the assertion failure message string and size information, which may lead to a buffer overflow if the message string size aligns to page size.

In the GNU C Library versions 2.1 to 2.44, calling tdelete on a sufficiently deep tree may write one pointer past the end of an alloca-allocated array on the stack, which may crash the application. The tdelete implementation keeps an explicit stack of parent nodes for rebalancing, which is grown as needed while descending the tree; two rebalancing branches push an additional entry without checking the capacity.

In GNU C Library versions 2.38 to 2.44, calling strfmon or strfmon_l can write past the end of the caller-supplied output buffer when a conversion uses right-justified width padding. Exploitation requires an application code path that calls these functions with right-justified width padding into a destination buffer large enough for the padding but too small for the internal memmove call. At the time of publication, no network-facing application impact is known.

The nscd service in the GNU C Library 2.3.4 onwards may crash due to a stack overflow when a malicious DNS server returns too large a response for a DNS query, resulting in degraded DNS resolution for the system. Exploitation requires nscd enabled and using an untrusted DNS server. There is also a remote possibility of nscd cache corruption.

Passing an effectively empty string to the `,ccs=` syntax extension of the mode argument in the `fopen` function in the GNU C Library version 2.45 or earlier may result in a heap buffer overflow when the mode string input to the function is attacker controlled. This usage pattern is not seen in applications in common GNU/Linux distributions and applications that process user-supplied values for `ccs` should not pass them through without validation.