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CVE-2026-59929VulnerabilityPublished

src/mistune/renderers/html.py blocks only javascript:, vbscript:, file · Prior to 3.3.0, the safe_url filter

Affects mistuneSource GCVE Database

0
Authoritative record:CVE-2026-59929· Medium 6.1

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

CVSS 3.1 base score
6.1Medium
How severe the flaw is on the 0–10 CVSS scale.
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu:16.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=xenialOther threatsAffected
  • =0.6-2
  • =0.7.1-1
Fixed in–
Ubuntu:18.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=bionicOther threatsAffected
  • =0.7.4-1
  • =0.8-1
  • =0.8.1-1
  • =0.8.3-2
Fixed in–
Ubuntu:20.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=focalOther threatsAffected
  • =0.8.4-1
  • =0.8.4-2
Fixed in–
Ubuntu:22.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=jammyOther threatsAffected
  • =0.8.4-4
  • =0.8.4-5
  • =2.0.0-1+really0.8.4-1
Fixed in–
Ubuntu:24.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=nobleOther threatsAffected
  • =2.0.4-2
  • =3.0.2-1
Fixed in–
Ubuntu:25.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=questingOther threatsAffected
  • =3.0.2-2
  • =3.1.3-1
Fixed in–
Ubuntu:26.04:LTSmistunepkg:deb/ubuntu/mistune?arch=source&distro=resoluteOther threatsAffected
  • =3.1.3-1
  • =3.1.4-1
Fixed in–
Homebrewadr-viewerpkg:brew/adr-viewerOther threatsAffected
  • >=1.3.0 <1.4.0_6
Fixed in
  • 1.4.0_6
Homebrewrecon-ngpkg:brew/recon-ngOther threatsAffected
  • >=5.1.1_1 <5.1.2_4
Fixed in
  • 5.1.2_4
Ubuntu:26.10mistunepkg:deb/ubuntu/mistune?arch=source&distro=stonkingOther threatsAffected
  • =3.1.4-1
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

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