CVE-2026-11404

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-09. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0

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

Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mg_tls_server_recv_hello(), which uses an attacker-controlled session_id_len byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated attacker can send a single crafted ClientHello with an oversized session id length to read past the receive buffer, crashing any HTTPS, MQTTS, or WSS service built on MG_TLS_BUILTIN.

CVSS v3
7.5
EG Score
7.5(high)
EPSS
35.7%
KEV
Not listed

Published

July 9, 2026

Last Modified

July 10, 2026

Advisory Details (4)

Auto-updated Jul 9, 2026
Patch available. Sources: github_commit, github_release.
generic

Cesanta Mongoose < 7.22 Out-of-Bounds Read in MG_TLS_BUILTIN ClientHello Session ID Parsing | Advisories | VulnCheck

https://www.vulncheck.com/advisories/cesanta-mongoose-out-of-bounds-read-in-mg-tls-builtin-clienthello-session-id-parsing
github_commit Patch Available

commit c288ac1f3842 (cesanta/mongoose)

Patch available: cesanta/mongoose 7.22 (contains commit c288ac1f3842)

https://github.com/cesanta/mongoose/commit/c288ac1f38424ffdd4d2fd5e1893fd4962642db3
generic

GitHub - cesanta/mongoose: Embedded web server, with TCP/IP network stack, MQTT and Websocket · GitHub

https://github.com/cesanta/mongoose
github_release Patch Available

7.22

Patch available: cesanta/mongoose 7.22

https://github.com/cesanta/mongoose/releases/tag/7.22

Vendor Advisories for CVE-2026-11404(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 32× in last 7d / 32× 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 15:29 UTCEG score recompute
  3. 2026-07-15 15:29 UTCGHSA enrichment
  4. 2026-07-15 03:29 UTCEG score recompute
  5. 2026-07-15 03:29 UTCGHSA enrichment
  6. 2026-07-15 02:00 UTCEPSS rescore
  7. 2026-07-14 15:31 UTCEG score recompute
  8. 2026-07-14 15:31 UTCGHSA enrichment
  9. 2026-07-14 03:32 UTCEG score recompute
  10. 2026-07-14 03:32 UTCGHSA enrichment
  11. 2026-07-13 22:30 UTCEPSS rescore
  12. 2026-07-13 15:34 UTCEG score recompute
  13. 2026-07-13 15:34 UTCGHSA enrichment
  14. 2026-07-13 06:12 UTCEPSS rescore
  15. 2026-07-13 03:34 UTCEG score recompute
  16. 2026-07-13 03:34 UTCGHSA enrichment
  17. 2026-07-12 15:35 UTCEG score recompute
  18. 2026-07-12 15:35 UTCGHSA enrichment
  19. 2026-07-12 05:46 UTCEPSS rescore
  20. 2026-07-12 03:36 UTCEG score recompute
  21. 2026-07-12 03:36 UTCGHSA enrichment
  22. 2026-07-11 15:38 UTCEG score recompute
  23. 2026-07-11 15:38 UTCGHSA enrichment
  24. 2026-07-11 08:27 UTCEPSS rescore
  25. 2026-07-11 03:39 UTCEG score recompute
Show 7 more
  1. 2026-07-11 03:38 UTCGHSA enrichment
  2. 2026-07-10 15:39 UTCEG score recompute
  3. 2026-07-10 15:39 UTCGHSA enrichment
  4. 2026-07-10 03:38 UTCEG score recompute
  5. 2026-07-10 03:38 UTCGHSA enrichment
  6. 2026-07-09 15:37 UTCEG score recompute
  7. 2026-07-09 15:35 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-11404?
CVE-2026-11404 is a high vulnerability published on July 9, 2026. Cesanta Mongoose before 7.22 contains an out-of-bounds read in the built-in TLS server function mgtlsserverrecvhello(), which uses an attacker-controlled sessionidlen byte from a TLS ClientHello as a buffer index without validating it against the length of received data. A remote, unauthenticated…
When was CVE-2026-11404 disclosed?
CVE-2026-11404 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-2026-11404 actively exploited?
CVE-2026-11404 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 35.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-11404?
CVE-2026-11404 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-11404?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-11404, 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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