Re: CVE-2026-29169: Apache HTTP Server: mod_dav_lock indirect lock crash

[Solar Designer <solar () openwall com>]

On Mon, May 04, 2026 at 02:15:25PM +0000, Eric Covener wrote:
> Severity: low 
>
> Affected versions:
>
> - Apache HTTP Server through 2.4.66
>
> Description:
>
> A NULL pointer dereference in mod_dav_lock in Apache HTTP Server 2.4.66 and earlier may allow an attacker to crash 
> the server with a malicious request.mod_dav_lock is not used internally by mod_dav or mod_dav_fs.
>
> The only known use-case for mod_dav_lock was mod_dav_svn from Apache Subversion earlier than version 1.2.0.
>
> Users are recommended to upgrade to version 2.4.66, which fixes this issue, or remove mod_dav_lock.

As confirmed by Eric off-list, the above line is erroneous.  It should
say "upgrade to version 2.4.67", not 2.4.66.  The website has it right:

https://httpd.apache.org/security/vulnerabilities_24.html

"Users are recommended to upgrade to version 2.4.67, which fixes this
issue, or remove mod_dav_lock."

> Credit:
>
> Pavel Kohout, Aisle Research, Aisle.com (finder)
>
> References:
>
> https://httpd.apache.org/security/vulnerabilities_24.html
> https://httpd.apache.org/
> https://www.cve.org/CVERecord?id=CVE-2026-29169
>
> Timeline:
>
> 2026-03-04: Report received
> 2026-05-04: 2.4.67 released
> 2026-05-04: fixed in 2.4.x by r1933354

Alexander