CVE-2026-4539: pygments archetype.py AdlLexer redos

Severity: low (CVSS 3.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-22 · updated 2026-06-17
Weakness: CWE-400

Description

A security flaw has been discovered in pygments up to 2.19.2. The impacted element is the function AdlLexer of the file pygments/lexers/archetype.py. The manipulation results in inefficient regular expression complexity. The attack is only possible with local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

Affected products

pygments: 2.19.0, 2.19.1, 2.19.2

References

https://github.com/pygments/pygments/
https://github.com/pygments/pygments/issues/3058
https://vuldb.com/?ctiid.352327
https://vuldb.com/?id.352327
https://vuldb.com/?submit.774685

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