CVE-2026-4539
pygments archetype.py AdlLexer redos
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.
INFO
Published Date :
March 22, 2026, 6:16 a.m.
Last Modified :
March 23, 2026, 2:31 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | LOW | [email protected] | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update pygments to version 2.19.3 or later.
- Monitor project for official security advisories.
- Apply any provided vendor patches or updates.
Public PoC/Exploit Available at Github
CVE-2026-4539 has a 12 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-4539.
| URL | Resource |
|---|---|
| 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 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-4539 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-4539
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-4539 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-4539 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Mar. 22, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Added CVSS V2 (AV:L/AC:L/Au:S/C:N/I:N/A:P) Added CWE CWE-400 Added CWE CWE-1333 Added Reference https://github.com/pygments/pygments/ Added Reference https://github.com/pygments/pygments/issues/3058 Added Reference https://vuldb.com/?ctiid.352327 Added Reference https://vuldb.com/?id.352327 Added Reference https://vuldb.com/?submit.774685