A memory calculation bug in mod_dav in Apache HTTP Server 2.4.67 and earlier leads to a shared lock overflow when an attacker issues a LOCK request that creates a WebDAV lock. The flaw is a mix of an Incorrect Length Calculation (CWE‑131) and an Integer/Buffer Overflow (CWE‑789) resulting from an improper memory sizing operation, which can corrupt the allocation and cause the server child process to crash.

All installations of Apache HTTP Server 2.4.67 or earlier that have the mod_dav module enabled and allow creation of WebDAV locks are susceptible. The issue is triggered when the module processes a lock request. The affected product is Apache HTTP Server, with the vendor being the Apache Software Foundation.

The vulnerability can be exploited by any account that has permission to issue WebDAV LOCK commands. An attacker sends an HTTP(S) request that creates a lock, which triggers the overflow and causes a child process to crash. This results in a denial‑of‑service condition. The CVSS score is 4.3, indicating moderate severity, while EPSS is not available and the flaw is not listed in the CISA KEV catalog. No code execution or data exfiltration is possible with this bug.