GHSL-2020-289: Regular Expression Denial of Service (ReDoS) in insane

published 2024-10-26 2 y ago modified 2026-06-17 4 mo ago also GHSA-w455-mfq9-hf74 , EUVD-2024-3148

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 45%
public exploits: 0; none known

insane is a whitelist-oriented HTML sanitizer. Versions 2.6.2 and prior contain one or more regular expressions that are vulnerable to Regular Expression Denial of Service (ReDoS). As of time of publication, no known patches are available.

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-2020-26303 updated 2025-11-21 cvss 7.5

insane: GHSL-2020-289: Regular Expression Denial of Service (ReDoS) in insane

Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/kibana6-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 (2024-10-28)

Exploit prediction

0.54% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

securitylab.github.com https://securitylab.github.com/advisories/GHSL-2020-289-redos-insane/ 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
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
GitHub	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	insane	<=2.6.2	no fix listed

Affected products

bevacqua insane

Classification

Weakness

CWE-1333 Inefficient Regular Expression Complexity

References

securitylab.github.com /advisories/GHSL-2020-289-redos-insane/
exploit, third-party-advisory
github.com /bevacqua/insane/issues/19
web, issue-tracking, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2020-26303
advisory
github.com /bevacqua/insane
package
securitylab.github.com /advisories/GHSL-2020-289-redos-insane
advisory

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.

Summary