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Fencer Vulns
high 7.5

CVE-2020-26311 json

GHSL-2020-312: Regular Expression Denial of Service (ReDoS) in useragent

published 2024-10-26 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-3081 , GHSA-mgfv-m47x-4wqp

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

Useragent is a user agent parser for Node.js. All versions as of time of publication contain one or more regular expressions that are vulnerable to Regular Expression Denial of Service (ReDoS). As of time of publication, no patches are available.

Patch / fix

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-2020-26311 updated cvss 7.5

Useragent: GHSL-2020-312: Regular Expression Denial of Service (ReDoS) in useragent

  • Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/kibana6-rhel8 Red Hat Quay 3 quay/quay-rhel8
    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
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • securitylab.github.com https://securitylab.github.com/advisories/GHSL-2020-312-redos-useragent/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Green
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/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:Green
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
npm useragent
<=2.3.0
 no fix listed

Affected products

  • 3rd-Eden useragent
  • useragent_project useragent

Classification

Weakness
  • CWE-1333 Inefficient Regular Expression Complexity

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.