src/mistune/renderers/html.py blocks only javascript:, vbscript:, file · Prior to 3.3.0, the safe_url filter
Affects mistuneSource GCVE Database
Not known to be exploited · CVSS 6.1 Medium : upgrade to 1.4.0_6 when convenient.
Data as of 26 Oct 2026, 09:16 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.4.0_6, 5.1.2_4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 8 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade adr-viewer to 1.4.0_6; recon-ng to 5.1.2_4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu:16.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=xenialOther threats | Affected
| Fixed in– |
Ubuntu:18.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=bionicOther threats | Affected
| Fixed in– |
Ubuntu:20.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu:22.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu:24.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu:25.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu:26.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Homebrewadr-viewerpkg:brew/adr-viewerOther threats | Affected
| Fixed in
|
Homebrewrecon-ngpkg:brew/recon-ngOther threats | Affected
| Fixed in
|
Ubuntu:26.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available that addresses this vulnerability. Users should upgrade to versions 1.4.0_6 or later and 5.1.2_4 or later where the issue is fixed. Applying these updates will mitigate the risk by properly filtering all unsafe URL schemes.
Description
CVE-2026-59929 is a medium severity vulnerability in the safe_url filter of the Mistune markdown renderer used by the adr-viewer component of recon-ng. The filter fails to block several legacy and chained URL schemes such as feed:, livescript:, view-source:, jar:, ms-its:, and mk:@MSITStore:, allowing attacker-controlled URLs with these schemes to bypass filtering. This can potentially lead to JavaScript execution in some vulnerable browsers. A patch is available to fix this issue.
References
- ubuntu.com/security/CVE-2026-59929 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-59929 (opens in a new tab)
- github.com/lepture/mistune/security/advisories/GHSA-qfrw-5rxm-mhh2 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-59929 (opens in a new tab)
- github.com/lepture/mistune/commit/c7101fcbb6e8790e8e39157c5ca2238fc6dd6cbc (opens in a new tab)
- github.com/lepture/mistune (opens in a new tab)
- github.com/lepture/mistune/releases/tag/v3.3.0 (opens in a new tab)
- github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2026-2217.yaml (opens in a new tab)