CVE-2026-16634 TOML::XS versions before 0.06 for Perl bundle an unsupported and vulnerable version of tomlc99
Attackers can cause denial of service via stack overflow by submitting deeply nested TOML documents to applications using vulnerable TOML::XS versions.
- 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-2026-16634?
CVE-2026-16634 is a critical denial of service vulnerability in FELIPE TOML::XS, published on 24 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
TOML::XS versions before 0.06 for Perl bundle an unsupported and vulnerable version of tomlc99.
The tomlc99 library is no longer maintained, and has an uncontrolled recursion vulnerability publicly reported in the issue tracker.
Any caller that passes untrusted TOML to from_toml risks a stack overflow from a deeply-nested document.
TOML::XS version 0.06 or later uses the successor tomlc17 library.
Which versions are affected by CVE-2026-16634?
How do I fix CVE-2026-16634?
No fix has been published for CVE-2026-16634 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-2026-16634 being exploited?
There is no known exploitation of CVE-2026-16634 in the wild and no public exploit code.
Sources
Also known as GHSA-hr7v-gv37-xpx2.