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.

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.

An insufficient entropy vulnerability was found in glibc. The getrandom and arc4random family of functions may return predictable randomness if these functions are called again after the fork, which happens concurrently with a call to any of these functions.

Passing too large an alignment to the memalign suite of functions (memalign, posix_memalign, aligned_alloc, valloc, pvalloc) 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.

A flaw was found in GLib. A denial of service on Windows platforms may occur if an application attempts to spawn a program using long command lines.

The regcomp function in the GNU C library version from 2.4 to 2.41 is subject to a double free if some previous allocation fails. It can be accomplished either by a malloc failure or by using an interposed malloc that injects random malloc failures. The double free can allow buffer manipulation depending of how the regex is constructed. This issue affects all architectures and ABIs supported by the GNU C library.

A flaw was found in GLib. GVariant deserialization is vulnerable to a slowdown issue where a crafted GVariant can cause excessive processing, leading to denial of service.