CVE-2026-11404

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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, GitHub Security Advisory, a secondary CVSS source
7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

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 (value × EchelonGraph’s weight)
Severity75% × 45%
The EG Score, 7.5 of 10.
Exploitation0.6% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.6%
EPSS %ILE
47th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 9, 2026

Last Modified

August 29, 2026

Advisory Details (4)

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

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
Web page

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.

Affected Packages

(1 across 1 ecosystem)
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
mongoose7.21+ds-1, 7.21+ds-1~bpo13+1, 7.21+ds-2, 7.22+ds-1~bpo13+1
  • every version up to 7.22+ds-1: fixed in 7.22+ds-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 34× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 228 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 128 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  2. 2026-10-12 16:37 UTCEG score recompute
  3. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  4. 2026-10-11 20:13 UTCEG score recompute
  5. 2026-10-11 18:25 UTCEG score recompute
  6. 2026-10-11 14:59 UTCEG score recompute
  7. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  8. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  9. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  10. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  11. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  12. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  13. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  14. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  15. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  16. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  17. 2026-10-01 16:02 UTCEG score recompute
  18. 2026-10-01 16:02 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  19. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  20. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  22. 2026-09-28 10:29 UTCEG score recompute
  23. 2026-09-28 10:29 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  24. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-09-24 11:25 UTCEG score recompute
Show 75 more
  1. 2026-09-24 11:25 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  2. 2026-09-23 13:47 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  3. 2026-09-23 05:56 UTCEG score recompute
  4. 2026-09-23 05:56 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  5. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  6. 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  7. 2026-09-18 05:36 UTCEG score recompute
  8. 2026-09-18 05:36 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  9. 2026-09-16 05:14 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  10. 2026-09-13 23:46 UTCEG score recompute
  11. 2026-09-13 23:46 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  12. 2026-09-13 16:46 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  13. 2026-09-13 08:19 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  14. 2026-09-12 15:29 UTCEG score recompute
  15. 2026-09-12 15:29 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-09-12 15:00 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  17. 2026-09-12 03:24 UTCEG score recompute
  18. 2026-09-12 03:24 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  19. 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  20. 2026-09-11 09:36 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  21. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  22. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  23. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  24. 2026-09-06 13:59 UTCEG score recompute
  25. 2026-09-06 13:59 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  26. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  27. 2026-09-05 22:35 UTCEG score recompute
  28. 2026-09-05 22:35 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  29. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  30. 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  31. 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  32. 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  33. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  34. 2026-08-30 18:45 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  35. 2026-08-30 06:46 UTCEG score recompute
  36. 2026-08-30 06:46 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  37. 2026-08-30 01:21 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  38. 2026-08-29 14:23 UTCEG score recompute
  39. 2026-08-29 14:23 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  40. 2026-08-29 13:46 UTCEG score recompute
  41. 2026-08-29 13:45 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  42. 2026-08-28 21:40 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  43. 2026-08-27 21:45 UTCEG score recompute
  44. 2026-08-27 21:45 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  45. 2026-08-27 14:24 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  46. 2026-08-27 01:09 UTCEG score recompute
  47. 2026-08-27 01:09 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  48. 2026-08-26 03:51 UTCEG score recompute
  49. 2026-08-26 03:51 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  50. 2026-08-25 13:48 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  51. 2026-08-25 10:07 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  52. 2026-08-24 20:20 UTCEG score recompute
  53. 2026-08-24 20:20 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  54. 2026-08-24 05:30 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  55. 2026-08-23 17:31 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  56. 2026-08-23 05:33 UTCEG score recompute
  57. 2026-08-23 05:33 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  58. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  59. 2026-08-22 17:34 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  60. 2026-08-22 03:47 UTCEG score recompute
  61. 2026-08-22 03:47 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  62. 2026-08-21 23:48 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  63. 2026-08-21 15:48 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  64. 2026-08-21 03:49 UTCEG score recompute
  65. 2026-08-21 03:49 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  66. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  67. 2026-08-20 15:17 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  68. 2026-08-20 01:49 UTCEG score recompute
  69. 2026-08-20 01:49 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  70. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  71. 2026-08-19 08:41 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  72. 2026-08-18 20:42 UTCEG score recompute
  73. 2026-08-18 20:42 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5
  74. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 27th percentile
  75. 2026-08-18 03:56 UTCGHSA enrichmentGHSA-cvgj-gr8r-q762 · GitHub severity HIGH · GitHub CVSS 7.5

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-11404?
CVE-2026-11404 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-11404 published?
The CVE record for CVE-2026-11404 was published on July 9, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of August 29, 2026; the record at its source may have been updated since.
Is CVE-2026-11404 actively exploited?
CVE-2026-11404 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (47th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-11404?
CVE-2026-11404 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-11404?
A fix for CVE-2026-11404 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-11404 are linked in the Vendor Advisories panel on this page.

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