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Fencer Vulns
low 3.3

CVE-2026-4539 json

pygments archetype.py AdlLexer redos

published 2026-03-22 7 mo ago modified 2026-09-10 1 mo ago also GHSA-5239-wwwm-4pmq , PYSEC-2026-2987 , EUVD-2026-14287

cvss
3.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

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.

Patch / fix

  • pypi pygments 2.20.0
  • pygments Debian 14 2.20.0+dfsg-1

debian advisories DEBIAN-CVE-2026-4539

  • python-Pygments SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 2.19.1-160000.3.1

suse advisories SUSE-SU-2026:22058-1SUSE-SU-2026:22093-1

  • python-Pygments openSUSE Leap 16.0 2.19.1-160000.3.1
  • python-Pygments openSUSE Tumbleweed 2.20.0-2.1

opensuse advisories openSUSE-SU-2026:20931-1openSUSE-SU-2026:10476-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-4539 updated cvss 3.3

pygments: Pygments: Denial of Service via inefficient regular expression processing in AdlLexer

  • Red Hat External Secrets Operator for Red Hat OpenShift external-secrets-operator/external-secrets-rhel9, external-secrets-operator/bitwarden-sdk-server-rhel9, external-secrets-operator/external-secrets-operator-rhel9, external-secrets-operator/external-secrets-operator-bundle Red Hat Lightspeed Core lightspeed-core/rag-tool-rhel9, lightspeed-core/lightspeed-stack-rhel9, lightspeed-core/dataverse-exporter-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed/lightspeed-to-dataverse-exporter-rhel9 Red Hat AI Inference Server rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, rhaiis/vllm-cuda-rhel9, rhaiis/vllm-rocm-rhel9, rhaiis/vllm-spyre-rhel9, rhaiis/vllm-neuron-rhel9, +1 more
    affected: no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-26/hub-rhel9, ansible-automation-platform-26/mcp-tools-rhel9, ansible-automation-platform-26/controller-rhel9, ansible-automation-platform-26/lightspeed-rhel9, ansible-automation-platform-25/ee-supported-rhel8, ansible-automation-platform-26/ee-supported-rhel9, +4 more
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Ansible Automation Platform Ansible Core 2 ansible-automation-platform-tech-preview/ee-minimal-rhel8, ansible-automation-platform-tech-preview/ee-minimal-rhel9 Red Hat Enterprise Linux 9 python3.14-pip, python3.14-pip-wheel Red Hat Enterprise Linux 10 python3.14-pip Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, rhelai3/bootc-azure-cuda-rhel9, rhelai3/bootc-azure-rocm-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-mlflow-rhel9, rhoai/odh-vllm-cpu-rhel9, rhoai/odh-vllm-cuda-rhel9, rhoai/odh-vllm-rocm-rhel9, rhoai/odh-caikit-nlp-rhel9, rhoai/odh-vllm-gaudi-rhel9, +37 more Red Hat OpenShift Container Platform 4 openshift4/ose-olm-catalogd-rhel9
    +1 more products
    Red Hat Satellite 6 satellite/iop-vmaas-rhel9, satellite/iop-puptoo-rhel9, satellite/foreman-mcp-server-rhel9, satellite/iop-host-inventory-rhel9, satellite/iop-vulnerability-engine-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Trusted Artifact Signer rhtas/model-transparency-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-24/lightspeed-rhel8, ansible-automation-platform-25/lightspeed-rhel8, ansible-automation-platform-26/ee-minimal-rhel9, ansible-automation-platform-26/ansible-dev-tools-rhel9, ansible-automation-platform-26/platform-resource-runner-rhel9 Red Hat Ansible Automation Platform Ansible Core 2 ansible-automation-platform/ee-minimal-rhel8, ansible-automation-platform/ee-minimal-rhel9 Red Hat Developer Hub 1 rhdh/rhdh-hub-rhel9 Red Hat Enterprise Linux 8 python3.11-pip, python3.12-pip, resource-agents, resource-agents-gcp, resource-agents-paf, python3.11-pip-wheel, +2 more Red Hat Enterprise Linux 9 python3.11-pip, python3.12-pip, python3.11-pip-wheel, python3.12-pip-wheel Red Hat Enterprise Linux 10 python-pip
    +4 more products
    Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/disk-image-cuda-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-model-registry-rhel8, rhoai/odh-caikit-tgis-serving-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-agent-installer-api-server-rhel9 Red Hat Satellite 6 satellite/iop-advisor-engine-rhel9, satellite/iop-insights-engine-rhel9
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/pygments/pygments/issues/3058 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 4.8 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
CNA 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA 3.0 3.3 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R
CNA 2.0 1.7 AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:ND/RC:UR
CNA 4.0 1.9 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/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
CNA 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
CNA 2.0 1.7 AV:L/AC:L/Au:S/C:N/I:N/A:P
GitHub 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 3.3 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
pypi pygments
<2.20.0
2.20.0

Affected products

  • n/a pygments

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.