CVE-2026-40890

github.com/gomarkdown/markdown: Out-of-bounds Read in SmartypantsRenderer

HIGH
7.5
CVSS Score
Published: April 21, 2026 at 07:51 PM UTC
Updated: October 26, 2026 at 09:10 PM UTC
1 product affected across 1 vendorMarkdown

Using markdown by gomarkdown?

Get instant alerts when new vulnerabilities affect markdown - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2026-04-10

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-125

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card