HOMEVULNERABILITIESCVE-2026-40890
HIGH

CVE-2026-40890

CWE-125Published: April 21, 2026· Updated: Apr 27, 2026

7.5
CVSS v3.1
EPSS:0.04%probability of exploitation in 30 daysPercentile:11.4th

Official Description

The package `github.com/gomarkdown/markdown` is a Go library for parsing Markdown text and rendering as HTML. Processing a malformed input containing a < character that is not followed by a > character anywhere in the remaining text with a SmartypantsRenderer will lead to Out of Bounds read or a panic. This vulnerability is fixed with commit 759bbc3e32073c3bc4e25969c132fc520eda2778.

NVD Source

Technical Analysis

CVE-2026-40890 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected Vendors & Products

gomarkdown1 product
markdown
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/gomarkdown/markdown/commit/759bbc3e32073c3bc4e25969c132fc520eda2778
ADVISORYhttps://github.com/gomarkdown/markdown/security/advisories/GHSA-77fj-vx54-gvh7
ADVISORYhttps://github.com/gomarkdown/markdown/security/advisories/GHSA-77fj-vx54-gvh7

All References (3)

→
https://github.com/gomarkdown/markdown/commit/759bbc3e32073c3bc4e25969c132fc520eda2778Patch
→
https://github.com/gomarkdown/markdown/security/advisories/GHSA-77fj-vx54-gvh7Exploit · Vendor Advisory
→
https://github.com/gomarkdown/markdown/security/advisories/GHSA-77fj-vx54-gvh7Exploit · Vendor Advisory

Quick Facts

CVE IDCVE-2026-40890
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-125
CISA KEVNo
EPSS (30d)0.04%
Affected1 vendor
PublishedApr 21, 2026

Related CVEs (CWE-125)

CVE-2026-34987
9.9
CVE-2026-24213
9.8
CVE-2026-42799
9.8
CVE-2025-15646
9.8
CVE-2026-33642
9.8
CVE-2026-11061
9.6

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2026-40890 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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