How severe is CVE-2026-44897?

CVE-2026-44897 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-2026-44897 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-44897?

CVE-2026-44897 affects Mistune Project Mistune. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-44897?

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

Does CVE-2026-44897 have an EU (EUVD) identifier?

Yes. CVE-2026-44897 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31994.

When was CVE-2026-44897 published?

CVE-2026-44897 was published on 2026-05-26 and last updated on 2026-06-17.

CVE-2026-44897

CVE-2026-44897 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% (14th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31994
Weakness: CWE-79
Affected product: Mistune Project Mistune
Published: 2026-05-26
Last modified: 2026-06-17

Description

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.

Frequently asked questions

What is CVE-2026-44897?: Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, HTMLRenderer.heading() builds the opening <hN> tag by string-concatenating the id attribute value directly into the HTML — with no call to escape(), safe_entity(), or any other sanitisation function. A double-quote character " in the id value terminates the attribute, allowing an attacker to inject arbitrary additional attributes (event handlers, src=, href=, etc.) into the heading element. This vulnerability is fixed in 3.2.1.
How severe is CVE-2026-44897?: CVE-2026-44897 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-2026-44897 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-44897?: CVE-2026-44897 affects Mistune Project Mistune. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-44897?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-44897 have an EU (EUVD) identifier?: Yes. CVE-2026-44897 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31994.
When was CVE-2026-44897 published?: CVE-2026-44897 was published on 2026-05-26 and last updated on 2026-06-17.

References

Affected products (1)

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

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