CVE-2026-44899

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Source
https://cve.org/CVERecord?id=CVE-2026-44899
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44899.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-44899
Aliases
Downstream
Related
Published
2026-05-26T20:36:40.461Z
Modified
2026-07-27T03:56:38.405471428Z
Severity
  • 4.7 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N CVSS Calculator
Summary
Mistune Image Directive CSS Injection Vulnerability
Details

Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.2.1, the Image directive plugin validates the :width: and :height: options with a regex compiled as numre = re.compile(r"^\d+(?:.\d*)?"). When the validated value is not a plain integer, renderblockimage() inserts it directly into a style="width:...;" or style="height:...;" attribute. Because the value was accepted by the prefix-only regex, any CSS after the leading digits reaches the style= attribute verbatim and without escaping. This vulnerability is fixed in 3.2.1.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44899.json",
    "cwe_ids": [
        "CWE-79"
    ],
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/lepture/mistune

Affected ranges

Type
GIT
Repo
https://github.com/lepture/mistune
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
067f90861088a496942f5eb43236135352b85d39
Database specific 
{
    "cpe": "cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*",
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE",
        "REFERENCES"
    ],
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "3.2.1"
        }
    ]
}

Affected versions

v0.*
v0.1.0
v0.2.0
v0.3.0
v0.3.1
v0.4
v0.4.1
v0.5
v0.5.1
v0.6
v0.7
v0.7.1
v0.7.2
v0.7.3
v0.7.4
v0.8
v0.8.1
v0.8.2
v0.8.3
v0.8.4
v2.*
v2.0.0
v2.0.0a1
v2.0.0a2
v2.0.0a3
v2.0.0a4
v2.0.0a5
v2.0.0a6
v2.0.0rc1
v2.0.1
v2.0.2
v3.*
v3.0.0
v3.0.0a1
v3.0.0a2
v3.0.0a3
v3.0.0rc1
v3.0.0rc2
v3.0.0rc3
v3.0.0rc4
v3.0.0rc5
v3.0.1
v3.1.0
v3.1.1
v3.1.2
v3.1.3
v3.1.4
v3.2.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44899.json"