Mistune: Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes
Affects mistuneSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 1.4.0_6 : patch mistune soon.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% 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:N/S:U/C:N/I:N/A:HExploitation 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– |
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 fixes the vulnerability by changing the parsing logic to linear time. Users should upgrade to Mistune versions 1.4.0_6 or later, or 5.1.2_4 or later, where the issue is resolved.
Description
CVE-2026-59928 is a denial-of-service vulnerability in the Mistune markdown parser used by recon-ng. The vulnerability arises from quadratic-time parsing when processing markdown documents containing many repeated or distinct reference-link definitions, which can exhaust CPU resources. A patch is available that changes the parsing logic to linear time, mitigating the issue.
References
- ubuntu.com/security/CVE-2026-59928 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-59928 (opens in a new tab)
- github.com/lepture/mistune/security/advisories/GHSA-ffq3-xpv3-j92q (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-59928 (opens in a new tab)
- github.com/lepture/mistune/commit/2b04d7ba341c16ac78fe82d3076bdd5c3de87c69 (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-2026-2216.yaml (opens in a new tab)