Buffer overflow in strfmon and strfmon_l right-justification padding

Calling strfmon and strfmon_l in the GNU C Library version 2.38 to 2.44 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 strfmon or strfmon_l with right-justified width padding into a destination buffer that is large enough for the padding to succeed but too small for the internal memmove call. The field width or format may be attacker-influenced or a fixed susceptible pattern in the caller. At the time of publication, no network-facing application impact is known.

wordexp with WRDE_APPEND can return or use invalid memory

Calling wordexp with WRDE_APPEND in the GNU C Library version 2.0 to version 2.43 can cause the interface to return invalid memory in the we_wordv member, which on subsequent calls to wordfree may abort the process.

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.

nscd: netgroup cache assumes NSS callback uses in-buffer strings

nscd: netgroup cache assumes NSS callback uses in-buffer strings The Name Service Cache Daemon's (nscd) netgroup cache can corrupt memory when the NSS callback does not store all strings in the provided buffer. The flaw was introduced in glibc 2.15 when the cache was added to nscd. This vulnerability is only present in the nscd binary.

nscd: netgroup cache may terminate daemon on memory allocation failure

nscd: netgroup cache may terminate daemon on memory allocation failure The Name Service Cache Daemon's (nscd) netgroup cache uses xmalloc or xrealloc and these functions may terminate the process due to a memory allocation failure resulting in a denial of service to the clients. The flaw was introduced in glibc 2.15 when the cache was added to nscd. This vulnerability is only present in the nscd binary.

nscd: Null pointer crashes after notfound response

nscd: Null pointer crashes after notfound response If the Name Service Cache Daemon's (nscd) cache fails to add a not-found netgroup response to the cache, the client request can result in a null pointer dereference. This flaw was introduced in glibc 2.15 when the cache was added to nscd. This vulnerability is only present in the nscd binary.

nscd: Stack-based buffer overflow in netgroup cache

nscd: Stack-based buffer overflow in netgroup cache If the Name Service Cache Daemon's (nscd) fixed size cache is exhausted by client requests then a subsequent client request for netgroup data may result in a stack-based buffer overflow. This flaw was introduced in glibc 2.15 when the cache was added to nscd. This vulnerability is only present in the nscd binary.

Glibc: integer overflow in __vsyslog_internal()

An integer overflow was found in the __vsyslog_internal 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 very long message, leading to an incorrect calculation of the buffer size to store the message, resulting in undefined behavior. This issue affects glibc 2.37 and newer.

Glibc: off-by-one heap-based buffer overflow in __vsyslog_internal()

An off-by-one heap-based buffer overflow was found in the __vsyslog_internal 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 INT_MAX 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.

Glibc: heap-based buffer overflow in __vsyslog_internal()

A heap-based buffer overflow was found in the __vsyslog_internal 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.

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.

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.

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.

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.

glibc NIS password hash disclosure

nis/nss_nis/nis-pwd.c in the GNU C Library (aka glibc or libc6) 2.7 and Embedded GLIBC (EGLIBC) 2.10.2 adds information from the passwd.adjunct.byname map to entries in the passwd map, which allows remote attackers to obtain the encrypted passwords of NIS accounts by calling the getpwnam function.

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.

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.

The Sun RPC functionality in multiple libc implementations does not provide a time-out mechanism when reading data from TCP connections, which allows remote attackers to cause a denial of service (hang).

security flaw

The BIND 4 and BIND 8.2.x stub resolver libraries, and other libraries such as glibc 2.2.5 and earlier, libc, and libresolv, use the maximum buffer size instead of the actual size when processing a DNS response, which causes the stub resolvers to read past the actual boundary ("read buffer overflow"), allowing remote attackers to cause a denial of service (crash).

security flaw

The unsetenv function in glibc 2.1.1 does not properly unset an environmental variable if the variable is provided twice to a program, which could allow local users to execute arbitrary commands in setuid programs by specifying their own duplicate environmental variables such as LD_PRELOAD or LD_LIBRARY_PATH.