Last updated 30 June 2026

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.

iconv crash due to assertion failure with untrusted input

Calling gethostbyaddr or gethostbyaddrr 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.

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

Calling getnetbyaddr or getnetbyaddrr 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.

Integer overflow in memalign leads to heap corruption

Untrusted LDLIBRARYPATH environment variable vulnerability in the GNU C Library version 2.27 to 2.38 allows attacker controlled loading of dynamically shared library in statically compiled setuid binaries that call dlopen (including internal dlopen calls after setlocale or calls to NSS functions such as getaddrinfo).

glibc is vulnerable to a denial of service, caused by a memory corruption by the Name Service Cache Daemon's (nscd) netgroup cache when the NSS callback fails to store all strings in the provided buffer. A local attacker could exploit this vulnerability to corrupt memory and cause a denial of service.

glibc is vulnerable to a denial of service, caused by a memory allocation failure when the Name Service Cache Daemon's (nscd) netgroup cache uses the xmalloc or xrealloc functions. A local attacker could exploit this vulnerability to terminate the daemon.

A stack-based buffer overflow in nscd was reported and assigned CVE-2024-33599.

Reference: https://sourceware.org/bugzilla/showbug.cgi?id=31677

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nscd/netgroupcache.c (addinnetgrX):

497 struct indataset 498 { 499 struct datahead head; 500 innetgroupresponseheader resp; 501 } dataset 502 = (struct indataset ) mempoolalloc (db, 503 sizeof (dataset) + req->keylen, 504 1);

mempoolalloc fails and returns NULL.

This is possible if posixfallocate fails and the retry fails.

505 struct indataset datasetmem; 506 bool cacheable = true; 507 if (glibcunlikely (dataset == NULL)) 508 { 509 cacheable = false; 510 dataset = &datasetmem;

This structure has no room for req->keylen material.

511 } 512 513 dataheadinitpos (&dataset->head, sizeof (dataset) + req->keylen, 514 sizeof (innetgroupresponseheader), 515 he == NULL ? 0 : dh->nreloads + 1, result->head.ttl); 516 / Set the notfound status and timeout based on the result from 517 getnetgrent. / 518 dataset->head.notfound = result->head.notfound; 519 dataset->head.timeout = timeout; 520 521 dataset->resp.version = NSCDVERSION; 522 dataset->resp.found = result->resp.found; 523 / Until we find a matching entry the result is 0. / 524 dataset->resp.result = 0; 525 526 char keycopy = memcpy ((char ) (dataset + 1), group, req->keylen);

This copies up to req->keylen material to a structure that has no storage space for it.

This was detected by static code analysis.

It will only happen in the case the database runs out of memory/storage while expanding the netgroup cache.

The group entries overwrite other data on the stack after datasetmem.

The workaround is not to cache the netgroup if this is impacting the use of the application.

GNU C Library could allow a remote attacker to execute arbitrary code on the system, caused by an out-of-bounds write in the ISO-2022-CN-EXT plugin. By sending specially crafted input, an attacker could exploit this vulnerability to overwrite critical data structures and execute arbitrary code on the system or cause the application to crash.

An off-by-one heap-based buffer overflow was found in the vsysloginternal function of the glibc library. This function is called by the syslog and vsyslog functions. This issue occurs when these functions are called with a message bigger than INTMAX bytes, leading to an incorrect calculation of the buffer size to store the message, resulting in an application crash. This issue affects glibc 2.37 and newer.

A heap-based buffer overflow was found in the vsysloginternal function of the glibc library. This function is called by the syslog and vsyslog functions. This issue occurs when the openlog function was not called, or called with the ident argument set to NULL, and the program name (the basename of argv[0]) is bigger than 1024 bytes, resulting in an application crash or local privilege escalation. This issue affects glibc 2.36 and newer.

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.

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

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.

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

GNU C Library (aka glibc or libc6) is vulnerable to a denial of service, caused by an assertion failure when processing invalid input sequences in the ISO-2022-JP-3 encoding in the iconv function. By sending specially-crafted input, a remote attacker could exploit this vulnerability to cause the application to crash.

A use-after-free vulnerability introduced in glibc upstream version 2.14 was found in the way the tilde expansion was carried out. Directory paths containing an initial tilde followed by a valid username were affected by this issue. A local attacker could exploit this flaw by creating a specially crafted path that, when processed by the glob function, would potentially lead to arbitrary code execution. This was fixed in version 2.32.

An out-of-bounds write vulnerability was found in glibc before 2.31 when handling signal trampolines on PowerPC. Specifically, the backtrace function did not properly check the array bounds when storing the frame address, resulting in a denial of service or potential code execution. The highest threat from this vulnerability is to system availability.

An exploitable signed comparison vulnerability exists in the ARMv7 memcpy() implementation of GNU glibc 2.30.9000. Calling memcpy() (on ARMv7 targets that utilize the GNU glibc implementation) with a negative value for the 'num' parameter results in a signed comparison vulnerability. If an attacker underflows the 'num' parameter to memcpy(), this vulnerability could lead to undefined behavior such as writing to out-of-bounds memory and potentially remote code execution. Furthermore, this memcpy() implementation allows for program execution to continue in scenarios where a segmentation fault or crash should have occurred. The dangers occur in that subsequent execution and iterations of this code will be executed with this corrupted data.

slim has NULL pointer dereference when using crypt() method from glibc 2.17

DISPUTED GNU Libc current is affected by: Re-mapping current loaded library with malicious ELF file. The impact is: In worst case attacker may evaluate privileges. The component is: libld. The attack vector is: Attacker sends 2 ELF files to victim and asks to run ldd on it. ldd execute code. NOTE: Upstream comments indicate "this is being treated as a non-security bug and no real threat."

DISPUTED In the GNU C Library (aka glibc or libc6) through 2.29, checkdstlimitscalcpos1 in posix/regexec.c has Uncontrolled Recursion, as demonstrated by '(|)(\\1\\1)' in grep, a different issue than CVE-2018-20796. NOTE: the software maintainer disputes that this is a vulnerability because the behavior occurs only with a crafted pattern.

In the GNU C Library (aka glibc or libc6) before 2.28, parseregexp in posix/regcomp.c misparses alternatives, which allows attackers to cause a denial of service (assertion failure and application exit) or trigger an incorrect result by attempting a regular-expression match.

In the GNU C Library (aka glibc or libc6) through 2.28, attempting to resolve a crafted hostname via getaddrinfo() leads to the allocation of a socket descriptor that is not closed. This is related to the ifnametoindex() function.

An AVX-512-optimized implementation of the mempcpy function in the GNU C Library (aka glibc or libc6) 2.27 and earlier may write data beyond the target buffer, leading to a buffer overflow in mempcpyavx512novzeroupper.

A buffer overflow in glibc 2.5 (released on September 29, 2006) and can be triggered through the LDLIBRARYPATH environment variable. Please note that many versions of glibc are not vulnerable to this issue if patched for CVE-2017-1000366.

A memory leak in glibc 2.1.1 (released on May 24, 1999) can be reached and amplified through the LDHWCAPMASK environment variable. Please note that many versions of glibc are not vulnerable to this issue if patched for CVE-2017-1000366.