CVE-2026-40890: github.com/gomarkdown/markdown: Out-of-bounds Read in SmartypantsRenderer
Vulnerability summary
CVE-2026-40890 is a high (CVSS 7.5) Out-of-bounds Read vulnerability in gomarkdown markdown. EPSS estimates a 0.35% chance of exploitation in the next 30 days, higher than 28.1% of scored vulnerabilities. 1 public exploit is recorded.
Public exploit (GitHub, Date unknown)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3 · Related 4Timeline
- 21-04-2026PublishedVulnerability first disclosed.
- 21-04-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
7 scores · 7 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · WolfiEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · GoEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · ChainguardEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.35%
Chance of exploitation in the next 30 days
Percentile
28%
Versus all other CVEs
30-day change
Decrease -0.17 pp
From 0.52% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundMarkdown
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard9 products
- fq< 0.17.0-r4
- gotenberg< 8.30.1-r2
- kube-metrics-adapter< 0.2.8-r8
- kube-metrics-adapter-fips< 0.2.8-r6
- snyk-cli< 1.1304.0-r1
Wolfi5 products
- fq< 0.17.0-r4
- kube-metrics-adapter< 0.2.8-r8
- snyk-cli< 1.1304.0-r1
- temporal< 1.7.0-r1
- temporal-ui-server< 2.48.3-r1
Debian1 product
- golang-github-gomarkdown-markdownAll versions (No fix recorded) | < 0.0~git20260725.8435af3-1
Github.com/gomarkdown1 product
- markdown< 0.0.0-20260411013819-759bbc3e3207
Gomarkdown1 product
- markdown< 759bbc3e32073c3bc4e25969c132fc520eda2778 | < 2026-04-10
Ubuntu1 product
- golang-github-gomarkdown-markdownAll versions (No fix recorded)
6 vendors · 18 products
References
8 links- github.com/gomarkdown/markdown/security/advisories/GHSA-77fj-vx54-gvh7X Refsource CONFIRMREPORTAdvisoryWEBExploitVendor Advisory
- github.com/gomarkdown/markdown/commit/759bbc3e32073c3bc4e25969c132fc520eda2778X Refsource MISCREPORTFIXWEBPatch
