CVE-2026-104454 YesWiki before 4.6.7 ReDoS via wakka.php Edit-Preview Endpoint
Unauthenticated attackers can cause denial of service in YesWiki by submitting crafted input to the edit-preview endpoint, saturating PHP-FPM workers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-104454?
CVE-2026-104454 is a medium-severity denial of service vulnerability in yeswiki, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
YesWiki before 4.6.7 contains an algorithmic-complexity denial of service in the wakka.php formatter due to an O(n^2) markdown-link regex. Unauthenticated attackers can submit a small crafted body of bracket characters to the page-edit preview endpoint to pin PHP-FPM workers and saturate the pool.
Weakness: CWE-1333
Which versions are affected by CVE-2026-104454?
How do I fix CVE-2026-104454?
No fix has been published for CVE-2026-104454 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-104454 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-104454 exists.
Sources
Also known as GHSA-gf57-wg5m-h34q, GHSA-j46p-q3g4-r6r6.