CVE-2026-40890
CVE-2026-40890 is a high-severity vulnerability in Gomarkdown Markdown with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 0% (27th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-24280
- Weakness: CWE-125
- Affected product: Gomarkdown Markdown
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-40890?
- 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.
- How severe is CVE-2026-40890?
- CVE-2026-40890 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-40890 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-40890?
- CVE-2026-40890 affects Gomarkdown Markdown. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-40890?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-40890 have an EU (EUVD) identifier?
- Yes. CVE-2026-40890 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-24280.
- When was CVE-2026-40890 published?
- CVE-2026-40890 was published on 2026-04-21 and last updated on 2026-06-17.
References
- https://github.com/gomarkdown/markdown/commit/759bbc3e32073c3bc4e25969c132fc520eda2778
- https://github.com/gomarkdown/markdown/security/advisories/GHSA-77fj-vx54-gvh7
Affected products (1)
- cpe:2.3:a:gomarkdown:markdown:*:*:*:*:*:go:*:*
More vulnerabilities in Gomarkdown Markdown
- CVE-2023-42821 — High (CVSS 7.5): The package `github.com/gomarkdown/markdown` is a Go library for parsing Markdown text and rendering as HTML. Prior to…
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