Wagtail regular expression denial-of-service via search query parsing

Vulnerability Description

Wagtail is an open source content management system built on Django. A bug in Wagtail's `parse_query_string` would result in it taking a long time to process suitably crafted inputs. When used to parse sufficiently long strings of characters without a space, `parse_query_string` would take an unexpectedly large amount of time to process, resulting in a denial of service. In an initial Wagtail installation, the vulnerability can be exploited by any Wagtail admin user. It cannot be exploited by end users. If your Wagtail site has a custom search implementation which uses `parse_query_string`, it may be exploitable by other users (e.g. unauthenticated users). Patched versions have been released as Wagtail 5.2.6, 6.0.6 and 6.1.3.

References

• https://github.com/wagtail/wagtail/security/advisories/GHSA-jmp3-39vp-fwg8
• https://github.com/wagtail/wagtail/commit/31b1e8532dfb1b70d8d37d22aff9cbde9109cdf2
• https://github.com/wagtail/wagtail/commit/3c941136f79c48446e3858df46e5b668d7f83797
• https://github.com/wagtail/wagtail/commit/b783c096b6d4fd2cfc05f9137a0be288850e99a2