CVE-2020-11888: python-markdown2 through 2.3.8 allows XSS because element names are mishandled unless a \w+ match succeeds

Q: How do I fix CVE-2020-11888?

python-markdown2: upgrade to newer than 2.3.8. Exact commands for each OS are on this page.

Q: Is CVE-2020-11888 being exploited?

CVE-2020-11888 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-2020-11888 affect?

CVE-2020-11888 affects python-markdown2. Severity is medium (CVSS 6.1). python-markdown2 through 2.3.8 allows XSS because element names are mishandled unless a \w+ match succeeds. For example, an attack might use elementname@ or elementname- with an onclick attribute.

Q: How urgent is CVE-2020-11888?

Priority 46/100. Public exploit reference

This month

MEDIUM 6.1UPGRADE

CVE-2020-11888 is a medium-severity flaw (CVSS 6.1) affecting python-markdown2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

python-markdown2 through 2.3.8 allows XSS because element names are mishandled unless a \w+ match succeeds. For example, an attack might use elementname@ or elementname- with an onclick attribute.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.9% (top 20%)
CISA exploited list	No
Weakness	CWE-79
Published	2020-04-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: python-markdown2 project

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

Am I affected?

Timeline

2020-04-20 16:15 UTCPublished CVE record published
2026-06-17 02:50 UTCUpdated Record last modified

python-markdown2 project python-markdown2 UPGRADE

Affected: <= 2.3.8

Fixed in: newer than 2.3.8

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy python-markdown2 || rpm -q python-markdown2 || python-markdown2 --version

2. UPGRADE to newer than 2.3.8 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade python-markdown2

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade python-markdown2

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-2020-11888?

python-markdown2: upgrade to newer than 2.3.8. Exact commands for each OS are on this page.

Is CVE-2020-11888 being exploited?

CVE-2020-11888 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-2020-11888 affect?

CVE-2020-11888 affects python-markdown2. Severity is medium (CVSS 6.1). python-markdown2 through 2.3.8 allows XSS because element names are mishandled unless a \w+ match succeeds. For example, an attack might use elementname@ or elementname- with an onclick attribute.

How urgent is CVE-2020-11888?

Priority 46/100. Public exploit reference

Software pages

Python vulnerabilities

Related CVEs

CVE-2009-3724 MEDIUM 6.1 UPGRADE python-markdown2 before 1.0.1.14 has multiple cross-site scripting (XSS) issues.

References

← Back to latest CVEs