CVE-2026-6368 in glibc
Summary
by MITRE • 08/10/2026
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.
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Analysis
by VulDB Data Team • 08/11/2026
The vulnerability described represents a critical memory management flaw in the GNU C Library's wordexp function implementation across versions 2.0 through 2.43. This issue stems from improper handling of the WRDE_APPEND flag during shell command expansion operations, creating a scenario where the wordexp function fails to properly initialize memory structures before populating the we_wordv member array. The flaw manifests when applications invoke wordexp with the WRDE_APPEND flag, which is designed to append words to an existing word list rather than replace it, but the library implementation does not correctly manage the memory allocation and initialization sequence for the output array.
The technical exploitation of this vulnerability occurs through a classic buffer overflow or memory corruption pattern where invalid pointers are written to the we_wordv array elements. When subsequent calls to wordfree attempt to release this malformed memory structure, the function encounters corrupted pointer values that trigger process termination or undefined behavior. This represents a direct violation of memory safety principles and falls under CWE-121 Stack-based Buffer Overflow or potentially CWE-787 Out-of-bounds Write depending on the specific memory layout. The vulnerability is particularly dangerous because it can be triggered through user-supplied input that gets processed by wordexp, making it a potential vector for privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple process crashes to encompass potential denial of service conditions in applications that rely heavily on shell command expansion functionality. Systems running vulnerable versions of glibc are at risk when processing untrusted input through functions that utilize wordexp with WRDE_APPEND, as attackers could craft malicious inputs that cause application crashes or potentially lead to more severe exploitation scenarios. The vulnerability affects a wide range of Unix-like systems including Linux distributions, BSD variants, and other platforms that depend on GNU libc for their standard library operations. This makes it particularly concerning from an enterprise security perspective where multiple applications may be simultaneously vulnerable.
Mitigation strategies should focus on immediate patching of affected glibc versions to the latest stable releases that contain the corrected wordexp implementation. Organizations should also implement input validation and sanitization measures when processing user-supplied data that might eventually reach wordexp functions, particularly avoiding the use of WRDE_APPEND flag in untrusted contexts. Additionally, system administrators should monitor for applications that make direct calls to wordexp and ensure they are running on patched systems. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter as it involves manipulation of shell command execution through library function flaws, while the technique could potentially map to T1203 Exploitation for Client Execution if exploited in web applications or other client-side contexts where user input flows through vulnerable code paths.