CyberSecBulletin
CVE-2026-16634NVD status: Deferred

TOML::XS: Use of Unmaintained Third Party Components

Published Updated By the CyberSecBulletin desk

CVE-2026-16634 is a critical-severity use of unmaintained third party components vulnerability in TOML::XS from FELIPE, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 0.06 as the first without the flaw, so updating TOML::XS to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.82% chance of exploitation within 30 days, higher than 58% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update TOML::XS to 0.06 or a later version.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
FELIPETOML::XSbefore 0.060.06

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).

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 The tomlc99 library is no longer maintained, and has an uncontrolled recursion vulnerability publicly reported in the issue tracker.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

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Use of Unmaintained Third Party Components

The product relies on third-party components that are not actively supported or maintained by the original developer or a trusted proxy for the original developer.

More Use of Unmaintained Third Party Components vulnerabilities (CWE-1104)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use of Unmaintained Third Party Components vulnerabilities

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