CVE-2026-50159

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.6%, top 55% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 5.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Prior to 10.9.8 and 11.16.1, Mermaid is vulnerable to CSS injection via sibling combinator selectors generated from diagram-supplied class or id names. An attacker who can supply diagram text can inject arbitrary CSS into the rendered page, potentially altering the appearance or behavior of unrelated page elements. This issue is fixed in versions 10.9.8 and 11.16.1.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
24(Track)
EG Risk 24/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
45%
KEV
Not listed

Published

August 6, 2026

Last Modified

August 7, 2026

Advisory Details (6)

Auto-updated Aug 6, 2026
Patch available. Sources: github, github_commit, github_pr, github_release.
github Patch Available

Mermaid allows CSS injection applying to sibling elements of the diagram · Advisory · mermaid-js/mermaid · GitHub

https://github.com/mermaid-js/mermaid/security/advisories/GHSA-6x64-9x62-f2gx
github_release Patch Available

v10.9.8

Patch available: mermaid-js/mermaid v10.9.8

https://github.com/mermaid-js/mermaid/releases/tag/v10.9.8
github_release Patch Available

[email protected]

Patch available: mermaid-js/mermaid [email protected]

https://github.com/mermaid-js/mermaid/releases/tag/[email protected]
github_pr Patch Available

Release Candidate 11.16.1

Patch available: mermaid-js/mermaid [email protected] (PR #8022 merged 2026-08-04)

https://github.com/mermaid-js/mermaid/pull/8022
github_commit Patch Available

commit 7e83f1533318 (mermaid-js/mermaid)

Patch available: mermaid-js/mermaid v10.9.8 (contains commit 7e83f1533318)

https://github.com/mermaid-js/mermaid/commit/7e83f1533318b307764d961906a73377266f4c5e
github_commit Patch Available

commit 12d472c9ed43 (mermaid-js/mermaid)

Patch available: mermaid-js/mermaid [email protected] (contains commit 12d472c9ed43)

https://github.com/mermaid-js/mermaid/commit/12d472c9ed43f94814b110da8d7a9ae6dd5266ed

Vendor Advisories for CVE-2026-50159(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(3 across 3 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
node-mermaid8.11.0+ds+~cs29.13.22-1 ... 9.2.2+~2.0.0-2 (15 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-mermaid8.11.0+ds+~cs29.13.22-1 ... 9.2.2+~2.0.0-2 (16 versions)——
npm(1)
PackageVulnerable rangeFixed inDependents
mermaid—10.9.8—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 27× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 22:55 UTCEPSS rescore
  2. 2026-08-20 14:18 UTCEG score recompute
  3. 2026-08-19 17:04 UTCEPSS rescore
  4. 2026-08-18 17:53 UTCEG score recompute
  5. 2026-08-18 13:48 UTCEPSS rescore
  6. 2026-08-17 19:24 UTCEG score recompute
  7. 2026-08-17 13:47 UTCEPSS rescore
  8. 2026-08-16 20:36 UTCEG score recompute
  9. 2026-08-16 14:56 UTCEPSS rescore
  10. 2026-08-16 02:14 UTCEPSS rescore
  11. 2026-08-15 22:47 UTCEG score recompute
  12. 2026-08-15 01:30 UTCEPSS rescore
  13. 2026-08-14 03:09 UTCEG score recompute
  14. 2026-08-13 22:00 UTCEPSS rescore
  15. 2026-08-13 05:20 UTCEG score recompute
  16. 2026-08-12 13:51 UTCEPSS rescore
  17. 2026-08-12 07:31 UTCEG score recompute
  18. 2026-08-11 09:42 UTCEG score recompute
  19. 2026-08-11 00:00 UTCEPSS rescore
  20. 2026-08-09 14:04 UTCEG score recompute
  21. 2026-08-09 13:46 UTCEPSS rescore
  22. 2026-08-08 16:37 UTCEPSS rescore
  23. 2026-08-07 18:27 UTCEG score recompute
  24. 2026-08-07 17:27 UTCEG score recompute
  25. 2026-08-06 22:19 UTCEG score recompute▲ 5.30
Show 2 more
  1. 2026-08-06 22:18 UTCNVD updateCVSS v3 → 5.3 · CVSS v4 → 5.3
  2. 2026-08-06 20:07 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-50159?
CVE-2026-50159 is a medium vulnerability published on August 6, 2026. Mermaid is a JavaScript tool that uses Markdown-inspired text to create and modify diagrams and charts. Prior to 10.9.8 and 11.16.1, Mermaid is vulnerable to CSS injection via sibling combinator selectors generated from diagram-supplied class or id names. An attacker who can supply diagram text can…
When was CVE-2026-50159 disclosed?
CVE-2026-50159 was first published in the National Vulnerability Database on August 6, 2026, with the most recent update on August 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-50159 actively exploited?
CVE-2026-50159 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 55.3% of all scored CVEs.
What is the CVSS score of CVE-2026-50159?
CVE-2026-50159 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-50159?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-50159, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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