CVE-2026-11404

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM 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 — 3 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: None knownExposed: 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(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity75% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
46%
KEV
Not listed

Published

July 9, 2026

Last Modified

August 29, 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 21× in last 7d / 109× 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.

Showing the most recent 100 of 169 total refreshes for this CVE.

  1. 2026-08-30 06:46 UTCEG score recompute
  2. 2026-08-30 06:46 UTCGHSA enrichment
  3. 2026-08-30 01:21 UTCEPSS rescore
  4. 2026-08-29 14:23 UTCEG score recompute
  5. 2026-08-29 14:23 UTCGHSA enrichment
  6. 2026-08-29 13:46 UTCEG score recompute
  7. 2026-08-29 13:45 UTCGHSA enrichment
  8. 2026-08-28 21:40 UTCEPSS rescore
  9. 2026-08-27 21:45 UTCEG score recompute
  10. 2026-08-27 21:45 UTCGHSA enrichment
  11. 2026-08-27 14:24 UTCEPSS rescore
  12. 2026-08-27 01:09 UTCEG score recompute
  13. 2026-08-27 01:09 UTCGHSA enrichment
  14. 2026-08-26 03:51 UTCEG score recompute
  15. 2026-08-26 03:51 UTCGHSA enrichment
  16. 2026-08-25 13:48 UTCEPSS rescore
  17. 2026-08-25 10:07 UTCGHSA enrichment
  18. 2026-08-24 20:20 UTCEG score recompute
  19. 2026-08-24 20:20 UTCGHSA enrichment
  20. 2026-08-24 05:30 UTCGHSA enrichment
  21. 2026-08-23 17:31 UTCGHSA enrichment
  22. 2026-08-23 05:33 UTCEG score recompute
  23. 2026-08-23 05:33 UTCGHSA enrichment
  24. 2026-08-23 00:19 UTCEPSS rescore
  25. 2026-08-22 17:34 UTCGHSA enrichment
Show 75 more
  1. 2026-08-22 03:47 UTCEG score recompute
  2. 2026-08-22 03:47 UTCGHSA enrichment
  3. 2026-08-21 23:48 UTCEPSS rescore
  4. 2026-08-21 15:48 UTCGHSA enrichment
  5. 2026-08-21 03:49 UTCEG score recompute
  6. 2026-08-21 03:49 UTCGHSA enrichment
  7. 2026-08-20 22:55 UTCEPSS rescore
  8. 2026-08-20 15:17 UTCGHSA enrichment
  9. 2026-08-20 01:49 UTCEG score recompute
  10. 2026-08-20 01:49 UTCGHSA enrichment
  11. 2026-08-19 17:03 UTCEPSS rescore
  12. 2026-08-19 08:41 UTCGHSA enrichment
  13. 2026-08-18 20:42 UTCEG score recompute
  14. 2026-08-18 20:42 UTCGHSA enrichment
  15. 2026-08-18 13:48 UTCEPSS rescore
  16. 2026-08-18 03:56 UTCGHSA enrichment
  17. 2026-08-17 15:57 UTCEG score recompute
  18. 2026-08-17 15:57 UTCGHSA enrichment
  19. 2026-08-17 03:59 UTCGHSA enrichment
  20. 2026-08-16 16:00 UTCEG score recompute
  21. 2026-08-16 16:00 UTCGHSA enrichment
  22. 2026-08-16 14:56 UTCEPSS rescore
  23. 2026-08-16 04:02 UTCEG score recompute
  24. 2026-08-16 04:02 UTCGHSA enrichment
  25. 2026-08-16 02:14 UTCEPSS rescore
  26. 2026-08-15 16:03 UTCGHSA enrichment
  27. 2026-08-15 04:04 UTCEG score recompute
  28. 2026-08-15 04:04 UTCGHSA enrichment
  29. 2026-08-15 01:30 UTCEPSS rescore
  30. 2026-08-14 16:05 UTCGHSA enrichment
  31. 2026-08-14 04:07 UTCEG score recompute
  32. 2026-08-14 04:07 UTCGHSA enrichment
  33. 2026-08-13 22:00 UTCEPSS rescore
  34. 2026-08-13 16:08 UTCGHSA enrichment
  35. 2026-08-13 04:10 UTCGHSA enrichment
  36. 2026-08-12 16:11 UTCEG score recompute
  37. 2026-08-12 16:11 UTCGHSA enrichment
  38. 2026-08-12 13:50 UTCEPSS rescore
  39. 2026-08-12 04:13 UTCGHSA enrichment
  40. 2026-08-11 16:15 UTCEG score recompute
  41. 2026-08-11 16:15 UTCGHSA enrichment
  42. 2026-08-11 13:42 UTCEPSS rescore
  43. 2026-08-11 04:16 UTCEG score recompute
  44. 2026-08-11 04:16 UTCGHSA enrichment
  45. 2026-08-10 23:59 UTCEPSS rescore
  46. 2026-08-10 16:18 UTCGHSA enrichment
  47. 2026-08-10 03:54 UTCGHSA enrichment
  48. 2026-08-09 15:55 UTCEG score recompute
  49. 2026-08-09 15:55 UTCGHSA enrichment
  50. 2026-08-09 13:46 UTCEPSS rescore
  51. 2026-08-09 03:57 UTCEG score recompute
  52. 2026-08-09 03:57 UTCGHSA enrichment
  53. 2026-08-08 16:37 UTCEPSS rescore
  54. 2026-08-08 15:59 UTCGHSA enrichment
  55. 2026-08-08 04:00 UTCEG score recompute
  56. 2026-08-08 04:00 UTCGHSA enrichment
  57. 2026-08-07 16:01 UTCGHSA enrichment
  58. 2026-08-07 04:02 UTCGHSA enrichment
  59. 2026-08-06 16:03 UTCEG score recompute
  60. 2026-08-06 16:03 UTCGHSA enrichment
  61. 2026-08-06 13:46 UTCEPSS rescore
  62. 2026-08-06 04:05 UTCEG score recompute
  63. 2026-08-06 04:05 UTCGHSA enrichment
  64. 2026-08-05 19:17 UTCEPSS rescore
  65. 2026-08-05 16:06 UTCGHSA enrichment
  66. 2026-08-05 04:07 UTCGHSA enrichment
  67. 2026-08-04 16:06 UTCEG score recompute
  68. 2026-08-04 16:06 UTCGHSA enrichment
  69. 2026-08-04 15:09 UTCEPSS rescore
  70. 2026-08-04 10:38 UTCEPSS rescore
  71. 2026-08-04 04:08 UTCGHSA enrichment
  72. 2026-08-03 16:09 UTCEG score recompute
  73. 2026-08-03 16:09 UTCGHSA enrichment
  74. 2026-08-03 10:35 UTCEPSS rescore
  75. 2026-08-03 04:10 UTCGHSA enrichment

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 August 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-11404 actively exploited?
CVE-2026-11404 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 53.6% of all scored CVEs.
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.

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