CVE-2026-4539
Pygments has Regular Expression Denial of Service (ReDoS) due to Inefficient Regex for GUID Matching
3.3
LOW
CVSS 3.1
EPSS 0.01%
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.
How to fix CVE-2026-4539
To remediate CVE-2026-4539, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 2.20.0 or later
Is CVE-2026-4539 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- from 0, < 2.20.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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/E:P |
| osv | CVSS 3.1 | LOW3.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L |