CVE-2026-4539 — Uncontrolled Resource Consumption in Pygments

CWE-400 — Uncontrolled Resource ConsumptionCWE-1333 — Regex Denial of Service7 documents6 sources
Severity
4.8MEDIUMNVD
EPSS
0.0%
top 97.32%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
PygmentsDebian Pygments
Timeline
PublishedMar 22

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.

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Affected Packages2 packages

▶PyPIpygments/pygments< 2.20.0

🔴Vulnerability Details

3
OSV
CVE-2026-4539: A security flaw has been discovered in pygments up to 2↗2026-03-22
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GHSA
Pygments has Regular Expression Denial of Service (ReDoS) due to Inefficient Regex for GUID Matching↗2026-03-22
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OSV
Pygments has Regular Expression Denial of Service (ReDoS) due to Inefficient Regex for GUID Matching↗2026-03-22
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📋Vendor Advisories

2
Red Hat
pygments: Pygments: Denial of Service via inefficient regular expression processing in AdlLexer↗2026-03-22
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Debian
CVE-2026-4539: pygments - A security flaw has been discovered in pygments up to 2.19.2. The impacted eleme...↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-4539 Impact, Exploitability, and Mitigation Steps | Wiz↗
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