CVE-2026-100691

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreHIGH confidence

Score 5.4 from GitHub Security Advisory published 2026-09-26. A secondary CVSS source baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Hugo versions 0.75.0 through 0.165.x contain a stored cross-site scripting vulnerability: the syntax highlighter does not escape the lineAnchors option before passing it to Chroma, which writes the value verbatim into the id and href attributes of the generated line-number markup. A crafted lineAnchors value supplied as a Markdown code fence attribute (or passed to the highlight template function) results in unescaped HTML in the rendered page, allowing arbitrary JavaScript to execute in the browsers of visitors to the generated site. This affects sites that build and publish Markdown from untrusted contributors; Hugo's security model otherwise considers content trusted input. Fixed in 0.166.0, where the lineAnchors value is HTML-escaped before being passed to Chroma.

CVSS v3
5.4
EG Score
5.4MEDIUMhigh confidence
EG Risk
24
EG Risk 24/100CISA SSVC

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
Severity54% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
5th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 26, 2026

Last Modified

September 29, 2026

Advisory Details (2)

Auto-updated Sep 26, 2026
Patch available. Sources: github.
generic

Hugo before 0.166.0 Stored XSS via lineAnchors code block option | Advisories | VulnCheck

https://www.vulncheck.com/advisories/hugo-before-0.166.0-stored-xss-via-lineanchors-code-block-option
github Patch Available

Stored XSS via unescaped lineAnchors code block option · Advisory · gohugoio/hugo · GitHub

Affected: v0.166.0. The

https://github.com/gohugoio/hugo/security/advisories/GHSA-q4xf-287f-98r8

Vendor Advisories for CVE-2026-100691(2)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhathugo-main-0.166.0-0.1.hum12026-09-09redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 28× in last 7d / 31× 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. 2026-10-04 03:47 UTCEG score recompute
  2. 2026-10-04 03:47 UTCVendor advisory
  3. 2026-10-04 03:47 UTCGHSA enrichment
  4. 2026-10-03 14:25 UTCEPSS rescore
  5. 2026-10-03 01:55 UTCEG score recompute
  6. 2026-10-03 01:55 UTCVendor advisory
  7. 2026-10-03 01:55 UTCGHSA enrichment
  8. 2026-10-02 00:02 UTCEG score recompute
  9. 2026-10-02 00:02 UTCVendor advisory
  10. 2026-10-02 00:02 UTCGHSA enrichment
  11. 2026-10-01 19:49 UTCEPSS rescore
  12. 2026-09-30 21:17 UTCEG score recompute
  13. 2026-09-30 21:17 UTCVendor advisory
  14. 2026-09-30 21:16 UTCGHSA enrichment
  15. 2026-09-30 15:02 UTCEPSS rescore
  16. 2026-09-29 19:22 UTCEG score recompute
  17. 2026-09-29 19:22 UTCVendor advisory
  18. 2026-09-29 19:22 UTCGHSA enrichment
  19. 2026-09-29 15:20 UTCEPSS rescore
  20. 2026-09-28 18:21 UTCEG score recompute
  21. 2026-09-28 18:21 UTCGHSA enrichment
  22. 2026-09-28 18:05 UTCEG score recompute
  23. 2026-09-28 18:04 UTCGHSA enrichment
  24. 2026-09-28 16:58 UTCEG score recompute
  25. 2026-09-28 16:58 UTCGHSA enrichment
Show 6 more
  1. 2026-09-28 13:50 UTCEPSS rescore
  2. 2026-09-27 16:23 UTCEG score recompute
  3. 2026-09-27 16:23 UTCGHSA enrichment
  4. 2026-09-26 14:31 UTCEG score recompute
  5. 2026-09-26 13:35 UTCEG score recompute
  6. 2026-09-26 13:30 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-100691?
CVE-2026-100691 is a medium vulnerability published on September 26, 2026. Hugo versions 0.75.0 through 0.165.x contain a stored cross-site scripting vulnerability: the syntax highlighter does not escape the lineAnchors option before passing it to Chroma, which writes the value verbatim into the id and href attributes of the generated line-number markup. A crafted…
When was CVE-2026-100691 disclosed?
CVE-2026-100691 was first published on September 26, 2026, with the most recent update on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-100691 actively exploited?
CVE-2026-100691 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (5th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-100691?
CVE-2026-100691 has a CVSS base score of 5.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-100691?
A fix for CVE-2026-100691 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-100691 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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