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Fencer Intel
critical 9.8

CVE-2026-16634 json

TOML::XS versions before 0.06 for Perl bundle an unsupported and vulnerable version of tomlc99

published 3mo ago modified 16d ago also EUVD-2026-48547

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 57%
public exploits
0
none known

Summary

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The tomlc99 library is no longer maintained, and has an uncontrolled recursion vulnerability publicly reported in the issue tracker.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.

Patch / fix

  • FELIPE TOML::XS 0.06

Is CVE-2026-16634 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
3mo ago

Exploit prediction

0.82% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/cktan/tomlc99/issues/97 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • FELIPE TOML::XS

Classification

Weakness
  • CWE-1104 Use of Unmaintained Third Party Components
  • CWE-1395 Dependency on Vulnerable Third-Party Component

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.