CVE-2026-15311

LOWPre-NVD 3.53.5—
EchelonGraph scoreHIGH confidence

Score 3.5 from GitHub Security Advisory (severity: LOW) published 2026-07-10. a secondary CVSS source baseline 3.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this weekElevated
3.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 3.5Exploit: NoneExposed: 0

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

A vulnerability was identified in NousResearch hermes-agent up to 2026.5.29.2. Affected by this issue is the function MatrixAdapter._markdown_to_html of the file gateway/platforms/matrix.py of the component Matrix Adapter. Such manipulation leads to cross site scripting. The attack can be executed remotely. The exploit is publicly available and might be used. The pull request to fix this issue awaits acceptance.

CVSS v3
3.5
EG Score
3.5(high)
EPSS
10.4%
KEV
Not listed

Published

July 9, 2026

Last Modified

July 10, 2026

References (7)

Vendor Advisories for CVE-2026-15311(1)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 15× 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. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 11:14 UTCEG score recompute
  3. 2026-07-15 11:14 UTCGHSA enrichment
  4. 2026-07-15 02:00 UTCEPSS rescore
  5. 2026-07-13 22:30 UTCEPSS rescore
  6. 2026-07-13 06:12 UTCEPSS rescore
  7. 2026-07-12 17:41 UTCEG score recompute
  8. 2026-07-12 17:41 UTCGHSA enrichment
  9. 2026-07-12 05:46 UTCEPSS rescore
  10. 2026-07-11 08:27 UTCEPSS rescore
  11. 2026-07-10 16:18 UTCNVD updateCVSS v4 → 2
  12. 2026-07-10 14:42 UTCMITRE cvelistV5CVSS v4 → 5.1
  13. 2026-07-10 01:47 UTCNVD updateCVSS v4 → 2
  14. 2026-07-10 00:09 UTCEG score recompute
  15. 2026-07-10 00:07 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-15311?
CVE-2026-15311 is a low vulnerability published on July 9, 2026. A vulnerability was identified in NousResearch hermes-agent up to 2026.5.29.2. Affected by this issue is the function MatrixAdapter.markdownto_html of the file gateway/platforms/matrix.py of the component Matrix Adapter. Such manipulation leads to cross site scripting. The attack can be executed…
When was CVE-2026-15311 disclosed?
CVE-2026-15311 was first published in the National Vulnerability Database on July 9, 2026, with the most recent update on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-15311 actively exploited?
CVE-2026-15311 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 10.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-15311?
CVE-2026-15311 has a CVSS v3 base score of 3.5 (NVD).
How do I remediate CVE-2026-15311?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-15311, 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

Explore the affected products and dependency analysis for CVE-2026-15311

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