UBUNTU-CVE-2026-67422

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Source
https://ubuntu.com/security/CVE-2026-67422
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-67422.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-67422
Upstream
Published
2026-08-06T22:18:00Z
Modified
2026-08-25T02:30:04Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
Details

pymdown-extensions is a collection of extensions for the Python Markdown library. In versions up to and including 11.0, four inline processors (caret, tilde, betterem, and magiclink) use regular expressions whose content groups can partition a run of delimiter characters in exponentially many ways, causing catastrophic backtracking. As a result, a single untrusted Markdown line under 50 bytes rendered with markdown.markdown() in each extension's default configuration drives the rendering thread into unbounded CPU usage that grows exponentially with input length, enabling an unauthenticated remote attacker who can submit Markdown to cause denial of service. The exposure is concrete for web applications that render user-supplied Markdown (comments, wikis, issue bodies, live preview), including any app using pymdownx.extra which bundles the vulnerable betterem default, as well as hosted docs/CI systems that build untrusted Markdown. The issue has been fixed in version 11.0.1.

References

Affected packages

Ubuntu:24.04:LTS / pymdown-extensions

Package

Name
pymdown-extensions
Purl
pkg:deb/ubuntu/pymdown-extensions?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

9.*
9.5-2
9.5-4
9.5-5

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-pymdownx",
            "binary_version": "9.5-5"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-67422.json"

Ubuntu:26.04:LTS / pymdown-extensions

Package

Name
pymdown-extensions
Purl
pkg:deb/ubuntu/pymdown-extensions?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

10.*
10.13-3
10.13-4
10.19.1-3

Ecosystem specific 

{
    "binaries": [
        {
            "binary_name": "python3-pymdownx",
            "binary_version": "10.19.1-3"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-67422.json"