How severe is CVE-2026-59929?

CVE-2026-59929 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2026-59929 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-59929?

CVE-2026-59929 affects Mistune Project Mistune. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-59929?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-59929 published?

CVE-2026-59929 was published on 2026-07-08 and last updated on 2026-07-09.

CVE-2026-59929

CVE-2026-59929 is a medium-severity vulnerability in Mistune Project Mistune with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Mistune Project Mistune
Published: 2026-07-08
Last modified: 2026-07-09

Description

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url filter in src/mistune/renderers/html.py blocks only javascript:, vbscript:, file:, and data: schemes, allowing legacy or chained schemes such as feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk:, and res: to reach rendered href and src attributes and potentially execute script in affected user agents. This issue is fixed in version 3.3.0.

Frequently asked questions

What is CVE-2026-59929?: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, the safe_url filter in src/mistune/renderers/html.py blocks only javascript:, vbscript:, file:, and data: schemes, allowing legacy or chained schemes such as feed:, view-source:, jar:, livescript:, mocha:, ms-its:, mk:, and res: to reach rendered href and src attributes and potentially execute script in affected user agents. This issue is fixed in version 3.3.0.
How severe is CVE-2026-59929?: CVE-2026-59929 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-59929 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-59929?: CVE-2026-59929 affects Mistune Project Mistune. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-59929?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-59929 published?: CVE-2026-59929 was published on 2026-07-08 and last updated on 2026-07-09.

References

Affected products (1)

cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*

More vulnerabilities in Mistune Project Mistune

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