CVE-2020-26303: insane is a whitelist-oriented HTML sanitizer

Q: How do I fix CVE-2020-26303?

insane: upgrade to newer than 2.6.2. Exact commands for each OS are on this page.

Q: Is CVE-2020-26303 being exploited?

CVE-2020-26303 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-26303 affect?

CVE-2020-26303 affects insane. Severity is high (CVSS 7.5). 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.

Q: How urgent is CVE-2020-26303?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2020-26303 is a high-severity flaw (CVSS 7.5) affecting insane. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-1333
Published	2024-10-26
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: bevacqua

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2024-10-26 21:15 UTCPublished CVE record published
2026-06-17 03:08 UTCUpdated Record last modified

bevacqua insane UPGRADE

Affected: <= 2.6.2

Fixed in: newer than 2.6.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy insane || rpm -q insane || insane --version

2. UPGRADE to newer than 2.6.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade insane

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade insane

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-26303?

insane: upgrade to newer than 2.6.2. Exact commands for each OS are on this page.

Is CVE-2020-26303 being exploited?

CVE-2020-26303 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-26303 affect?

CVE-2020-26303 affects insane. Severity is high (CVSS 7.5). 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.

How urgent is CVE-2020-26303?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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