CVE-2026-100521

MEDIUMPre-NVD 6.16.1—
EchelonGraph scoreHIGH confidence

Score 6.1 from GitHub Security Advisory published 2026-09-26. A secondary CVSS source baseline 6.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.1Exploit: None knownExposed services: Not assessed

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

Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in the search plugin highlight parameter that performs no HTML or JavaScript escaping. Attackers can craft malicious links with injected JavaScript in the highlight parameter that executes in the browser of any visitor who opens the link, including administrators.

CVSS v3
6.1
EG Score
6.1MEDIUMhigh confidence
EG Risk
28
EG Risk 28/100CISA 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
Severity61% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.
EPSS PROB
0.2%
EPSS %ILE
8th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines, and watch the vendor's advisory for the fix.

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 (6)

Auto-updated Sep 26, 2026
No patch confirmed yet. Sources: github_pr.
generic

Cotonti through 1.0.0 Reflected XSS via search highlight parameter | Advisories | VulnCheck

https://www.vulncheck.com/advisories/cotonti-through-1.0.0-reflected-xss-via-search-highlight-parameter
github_pr

Security hardening (batch 1): CSRF tokens, XSS escaping, redirect validation, CSPRNG tokens, upload & object-injection fixes

Upstream fix in progress (PR #1908 · Cotonti/Cotonti, state=open)

https://github.com/Cotonti/Cotonti/pull/1908
generic

Security: ~60 confirmed vulnerabilities in current master (f43f1fc) — CSRF, XSS, open redirect, weak tokens, upload/RCE chains (coordinated disclosure via VulnCheck CNA) · Issue #1907 · Cotonti/Cotonti · GitHub

https://github.com/Cotonti/Cotonti/issues/1907
generic

Cotonti/plugins/search/search.page.first.php at 1.0.0 · Cotonti/Cotonti · GitHub

https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/search/search.page.first.php
generic

Cotonti/plugins/search/search.header.php at 1.0.0 · Cotonti/Cotonti · GitHub

https://github.com/Cotonti/Cotonti/blob/1.0.0/plugins/search/search.header.php
generic

GitHub - Cotonti/Cotonti: Fast, reliable and flexible PHP CMF/CMS · GitHub

https://github.com/Cotonti/Cotonti

Vendor Advisories for CVE-2026-100521(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 21× in last 7d / 29× 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 23:21 UTCEPSS rescore
  2. 2026-10-04 15:13 UTCGHSA enrichment
  3. 2026-10-03 15:50 UTCEG score recompute
  4. 2026-10-03 15:49 UTCGHSA enrichment
  5. 2026-10-03 14:25 UTCEPSS rescore
  6. 2026-10-02 16:24 UTCGHSA enrichment
  7. 2026-10-02 16:23 UTCEG score recompute
  8. 2026-10-02 16:23 UTCGHSA enrichment
  9. 2026-10-01 19:49 UTCEPSS rescore
  10. 2026-10-01 17:01 UTCGHSA enrichment
  11. 2026-09-30 17:40 UTCEG score recompute
  12. 2026-09-30 17:40 UTCGHSA enrichment
  13. 2026-09-30 15:02 UTCEPSS rescore
  14. 2026-09-29 18:17 UTCEG score recompute
  15. 2026-09-29 18:17 UTCGHSA enrichment
  16. 2026-09-29 17:37 UTCEG score recompute
  17. 2026-09-29 17:37 UTCGHSA enrichment
  18. 2026-09-29 15:20 UTCEPSS rescore
  19. 2026-09-28 23:24 UTCEG score recompute
  20. 2026-09-28 23:24 UTCGHSA enrichment
  21. 2026-09-28 13:50 UTCEPSS rescore
  22. 2026-09-28 00:03 UTCEG score recompute
  23. 2026-09-28 00:03 UTCGHSA enrichment
  24. 2026-09-27 00:42 UTCEG score recompute
  25. 2026-09-27 00:42 UTCGHSA enrichment
Show 4 more
  1. 2026-09-26 15:58 UTCEPSS rescore
  2. 2026-09-26 01:20 UTCEG score recompute
  3. 2026-09-26 01:11 UTCEG score recompute
  4. 2026-09-26 01:09 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-100521?
CVE-2026-100521 is a medium vulnerability published on September 26, 2026. Cotonti through 1.0.0 contains a reflected cross-site scripting vulnerability in the search plugin highlight parameter that performs no HTML or JavaScript escaping. Attackers can craft malicious links with injected JavaScript in the highlight parameter that executes in the browser of any visitor…
When was CVE-2026-100521 disclosed?
CVE-2026-100521 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-2026-100521 actively exploited?
CVE-2026-100521 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (8th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-100521?
CVE-2026-100521 has a CVSS base score of 6.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-100521?
No fix for CVE-2026-100521 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-100521 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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