How severe is CVE-2026-16634?

CVE-2026-16634 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-16634 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-16634?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-16634 published?

CVE-2026-16634 was published on 2026-07-24 and last updated on 2026-07-27.

CVE-2026-16634

CVE-2026-16634 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1104.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 1% (53rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-1104
Published: 2026-07-24
Last modified: 2026-07-27

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 The tomlc99 library is no longer maintained, and has an uncontrolled recursion vulnerability publicly reported in the issue tracker.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

Frequently asked questions

What is CVE-2026-16634?: 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 The tomlc99 library is no longer maintained, and has an uncontrolled recursion vulnerability publicly reported in the issue tracker.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.
How severe is CVE-2026-16634?: CVE-2026-16634 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-16634 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (53rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-16634?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-16634 published?: CVE-2026-16634 was published on 2026-07-24 and last updated on 2026-07-27.

References

Other CWE-1104 vulnerabilities

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