Is CVE-2026-40890 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40890 being exploited in the wild.

How severe is CVE-2026-40890?

High severity, with a CVSS score of 7.5, published 21 April 2026.

Which products and versions are affected?

github.com/gomarkdown/markdown (Go) < 0.0.0-20260411013819-759bbc3e3207, SEMVER:introduced=0,fixed=0.0.0-20260411013819-759bbc3e3207.

Is there a fix for CVE-2026-40890?

Yes. github.com/gomarkdown/markdown (Go): upgrade to 0.0.0-20260411013819-759bbc3e3207 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Am I affected by CVE-2026-40890?

Check whether you run github.com/gomarkdown/markdown (Go) or Gomarkdown Markdown at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-40890: Go Markdown has an Out-of-bounds Read in SmartypantsRenderer

Q: Is there a fix for CVE-2026-40890?

Yes. github.com/gomarkdown/markdown (Go): upgrade to 0.0.0-20260411013819-759bbc3e3207 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: Am I affected by CVE-2026-40890?

Check whether you run github.com/gomarkdown/markdown (Go) or Gomarkdown Markdown at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-40890 · Severity: high · CVSS 7.5 · Published 2026-04-21

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.

Technologies: github.com/gomarkdown/markdown (Go). Vendors: Go.

Quick answers

Is CVE-2026-40890 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-40890 being exploited in the wild.
How severe is CVE-2026-40890?: High severity, with a CVSS score of 7.5, published 21 April 2026.
Which products and versions are affected?: github.com/gomarkdown/markdown (Go) < 0.0.0-20260411013819-759bbc3e3207, SEMVER:introduced=0,fixed=0.0.0-20260411013819-759bbc3e3207.
Is there a fix for CVE-2026-40890?: Yes. github.com/gomarkdown/markdown (Go): upgrade to 0.0.0-20260411013819-759bbc3e3207 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-40890?: Check whether you run github.com/gomarkdown/markdown (Go) or Gomarkdown Markdown at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/gomarkdown/markdown (Go): upgrade to 0.0.0-20260411013819-759bbc3e3207 or later
```
go get github.com/gomarkdown/markdown@v0.0.0-20260411013819-759bbc3e3207
```

Affected products

github.com/gomarkdown/markdown (Go) < 0.0.0-20260411013819-759bbc3e3207, SEMVER:introduced=0,fixed=0.0.0-20260411013819-759bbc3e3207
Gomarkdown Markdown

Identifiers

CVE-2026-40890
GHSA-77fj-vx54-gvh7
GO-2026-5208

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.