Vulnerabilidades do Gnu Glibc

CVE-2026-6238 Média · 6.5 CWE-126 28/04/2026

Buffer overread in ns_printrrf with corrupted RDATA field

The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.0.1 to version 2.43 fail to validate the RDATA content against the RDATA length in a DNS response when processing A6, CERT, LOC, TKEY or TSIG records, which may allow an attacker to craft a DNS response, causing a target application to crash or read uninitialized memory. These functions are for application debugging only and hence not in the path of code executed by the DNS resolver. Further, they have been deprecated since version 2.34 and should not be used by any new applications. Applications should consider porting away from these interfaces since they may be removed in future versions.

CVE-2026-5435 Alta · 7.3 CWE-787 28/04/2026

Potential buffer overflow in ns_sprintrrf TSIG handling path

The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.2 and newer fail to enforce the caller-supplied buffer length, and can result in an out-of-bounds write when printing TSIG records.

CVE-2026-5928 Alta · 7.5 CWE-127 20/04/2026

Potential buffer under-read in ungetwc

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.

CVE-2026-5450 Crítica · 9.8 CWE-787 20/04/2026

scanf %mc off-by-one heap buffer overflow

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-2026-4046 Alta · 7.5 CWE-617 30/03/2026

iconv crash due to assertion failure with untrusted input

The iconv() function in the GNU C Library versions 2.43 and earlier may crash due to an assertion failure when converting inputs from the IBM1390 or IBM1399 character sets, which may be used to remotely crash an application. This vulnerability can be trivially mitigated by removing the IBM1390 and IBM1399 character sets from systems that do not need them.

CVE-2026-4438 Média · 5.4 CWE-20 20/03/2026

gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.

CVE-2026-4437 Alta · 7.5 CWE-125 20/03/2026

gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.

CVE-2026-3904 Média · 6.2 CWE-366 11/03/2026

Calling NSS-backed functions that support caching via nscd may call the nscd client side…

Calling NSS-backed functions that support caching via nscd may call the nscd client side code and in the GNU C Library version 2.36 under high load on x86_64 systems, the client may call memcmp on inputs that are concurrently modified by other processes or threads and crash. The nscd client in the GNU C Library uses the memcmp function with inputs that may be concurrently modified by another thread, potentially resulting in spurious cache misses, which in itself is not a security issue. However in the GNU C Library version 2.36 an optimized implementation of memcmp was introduced for x86_64 which could crash when invoked with such undefined behaviour, turning this into a potential crash of the nscd client and the application that uses it. This implementation was backported to the 2.35 branch, making the nscd client in that branch vulnerable as well. Subsequently, the fix for this issue was backported to all vulnerable branches in the GNU C Library repository. It is advised that distributions that may have cherry-picked the memcpy SSE2 optimization in their copy of the GNU C Library, also apply the fix to avoid the potential crash in the nscd client.

CVE-2025-15281 Alta · 7.5 CWE-908 20/01/2026

wordexp with WRDE_REUSE and WRDE_APPEND may return uninitialized memory

Calling wordexp with WRDE_REUSE in conjunction with WRDE_APPEND in the GNU C Library version 2.0 to version 2.42 may cause the interface to return uninitialized memory in the we_wordv member, which on subsequent calls to wordfree may abort the process.

CVE-2026-0915 Alta · 7.5 CWE-908 15/01/2026

getnetbyaddr and getnetbyaddr_r leak stack contents to DNS resovler

Calling getnetbyaddr or getnetbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend for networks and queries for a zero-valued network in the GNU C Library version 2.0 to version 2.42 can leak stack contents to the configured DNS resolver.

CVE-2026-0861 Alta · 8.4 CWE-190 14/01/2026

Integer overflow in memalign leads to heap corruption

Passing too large an alignment to the memalign suite of functions (memalign, posix_memalign, aligned_alloc) in the GNU C Library version 2.30 to 2.42 may result in an integer overflow, which could consequently result in a heap corruption. Note that the attacker must have control over both, the size as well as the alignment arguments of the memalign function to be able to exploit this. The size parameter must be close enough to PTRDIFF_MAX so as to overflow size_t along with the large alignment argument. This limits the malicious inputs for the alignment for memalign to the range [1<<62+ 1, 1<<63] and exactly 1<<63 for posix_memalign and aligned_alloc. Typically the alignment argument passed to such functions is a known constrained quantity (e.g. page size, block size, struct sizes) and is not attacker controlled, because of which this may not be easily exploitable in practice. An application bug could potentially result in the input alignment being too large, e.g. due to a different buffer overflow or integer overflow in the application or its dependent libraries, but that is again an uncommon usage pattern given typical sources of alignments.

CVE-2023-4911 Alta · 7.8 KEV Urgente · 76 Exploit público CWE-787 03/10/2023

GNU C Library Buffer Overflow Vulnerability

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.

CVE-2023-5156 Alta · 7.5 CWE-401 25/09/2023

Glibc: dos due to memory leak in getaddrinfo.c

A flaw was found in the GNU C Library. A recent fix for CVE-2023-4806 introduced the potential for a memory leak, which may result in an application crash.

CVE-2023-4806 Média · 5.9 CWE-416 18/09/2023

Glibc: potential use-after-free in getaddrinfo()

A flaw has been identified in glibc. In an extremely rare situation, the getaddrinfo function may access memory that has been freed, resulting in an application crash. This issue is only exploitable when a NSS module implements only the _nss_*_gethostbyname2_r and _nss_*_getcanonname_r hooks without implementing the _nss_*_gethostbyname3_r hook. The resolved name should return a large number of IPv6 and IPv4, and the call to the getaddrinfo function should have the AF_INET6 address family with AI_CANONNAME, AI_ALL and AI_V4MAPPED as flags.

CVE-2023-4813 Média · 5.9 CWE-416 12/09/2023

Glibc: potential use-after-free in gaih_inet()

A flaw has been identified in glibc. In an uncommon situation, the gaih_inet function may use memory that has been freed, resulting in an application crash. This issue is only exploitable when the getaddrinfo function is called and the hosts database in /etc/nsswitch.conf is configured with SUCCESS=continue or SUCCESS=merge.

CVE-2023-0687 Crítica · 9.8 CWE-120 06/02/2023

A vulnerability was found in GNU C Library 2.38. It has been declared as critical. This...

A vulnerability was found in GNU C Library 2.38. It has been declared as critical. This vulnerability affects the function __monstartup of the file gmon.c of the component Call Graph Monitor. The manipulation leads to buffer overflow. It is recommended to apply a patch to fix this issue. VDB-220246 is the identifier assigned to this vulnerability. NOTE: The real existence of this vulnerability is still doubted at the moment. The inputs that induce this vulnerability are basically addresses of the running application that is built with gmon enabled. It's basically trusted input or input that needs an actual security flaw to be compromised or controlled.

CVE-2023-25139 Crítica · 9.8 CWE-787 03/02/2023

sprintf in the GNU C Library (glibc) 2.37 has a buffer overflow (out-of-bounds write) in some...

sprintf in the GNU C Library (glibc) 2.37 has a buffer overflow (out-of-bounds write) in some situations with a correct buffer size. This is unrelated to CWE-676. It may write beyond the bounds of the destination buffer when attempting to write a padded, thousands-separated string representation of a number, if the buffer is allocated the exact size required to represent that number as a string. For example, 1,234,567 (with padding to 13) overflows by two bytes.

CVE-2021-3999 Alta · 7.8 CWE-193 24/08/2022

A flaw was found in glibc. An off-by-one buffer overflow and underflow in getcwd() may lead to...

A flaw was found in glibc. An off-by-one buffer overflow and underflow in getcwd() may lead to memory corruption when the size of the buffer is exactly 1. A local attacker who can control the input buffer and size passed to getcwd() in a setuid program could use this flaw to potentially execute arbitrary code and escalate their privileges on the system.

CVE-2021-3998 Alta · 7.5 CWE-125 24/08/2022

A flaw was found in glibc. The realpath() function can mistakenly return an unexpected value,...

A flaw was found in glibc. The realpath() function can mistakenly return an unexpected value, potentially leading to information leakage and disclosure of sensitive data.

CVE-2022-23219 Crítica · 9.8 CWE-120 14/01/2022

The deprecated compatibility function clnt_create in the sunrpc module of the GNU C Library (aka...

The deprecated compatibility function clnt_create in the sunrpc module of the GNU C Library (aka glibc) through 2.34 copies its hostname argument on the stack without validating its length, which may result in a buffer overflow, potentially resulting in a denial of service or (if an application is not built with a stack protector enabled) arbitrary code execution.

CVE-2022-23218 Crítica · 9.8 CWE-120 14/01/2022

The deprecated compatibility function svcunix_create in the sunrpc module of the GNU C Library ...

The deprecated compatibility function svcunix_create in the sunrpc module of the GNU C Library (aka glibc) through 2.34 copies its path argument on the stack without validating its length, which may result in a buffer overflow, potentially resulting in a denial of service or (if an application is not built with a stack protector enabled) arbitrary code execution.

CVE-2021-43396 Alta · 7.5 04/11/2021

In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force...

In iconvdata/iso-2022-jp-3.c in the GNU C Library (aka glibc) 2.34, remote attackers can force iconv() to emit a spurious '\0' character via crafted ISO-2022-JP-3 data that is accompanied by an internal state reset. This may affect data integrity in certain iconv() use cases. NOTE: the vendor states "the bug cannot be invoked through user input and requires iconv to be invoked with a NULL inbuf, which ought to require a separate application bug to do so unintentionally. Hence there's no security impact to the bug.

CVE-2021-38604 Alta · 7.5 CWE-476 12/08/2021

NULL Pointer Dereference em Gnu Glibc

In librt in the GNU C Library (aka glibc) through 2.34, sysdeps/unix/sysv/linux/mq_notify.c mishandles certain NOTIFY_REMOVED data, leading to a NULL pointer dereference. NOTE: this vulnerability was introduced as a side effect of the CVE-2021-33574 fix.

CVE-2021-35942 Crítica · 9.1 CWE-190 22/07/2021

The wordexp function in the GNU C Library (aka glibc) through 2.33 may crash or read arbitrary...

The wordexp function in the GNU C Library (aka glibc) through 2.33 may crash or read arbitrary memory in parse_param (in posix/wordexp.c) when called with an untrusted, crafted pattern, potentially resulting in a denial of service or disclosure of information. This occurs because atoi was used but strtoul should have been used to ensure correct calculations.

CVE-2021-33574 Crítica · 9.8 CWE-416 25/05/2021

The mq_notify function in the GNU C Library (aka glibc) through 2.33 has a use-after-free. It may...

The mq_notify function in the GNU C Library (aka glibc) versions 2.32 and 2.33 has a use-after-free. It may use the notification thread attributes object (passed through its struct sigevent parameter) after it has been freed by the caller, leading to a denial of service (application crash) or possibly unspecified other impact.