CVE-2026-101003

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreMEDIUM confidence

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

Score 5.3 from GitHub Security Advisory published 2026-09-28. A secondary CVSS source baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week

Also known asEUVD-2026-88089 (ENISA EUVD) · GHSA-g7gm-388f-77vf (GitHub Security Advisories)Source: ENISA EUVD

5.3EG
EchelonGraph verdictMonitorRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A weakness has been identified in Cesanta Mongoose up to 7.21. Affected by this vulnerability is the function fn of the file tutorials/mqtt/mqtt-server/main.c of the component MQTT Broker. Executing a manipulation can lead to stack-based buffer overflow. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 7.22 addresses this issue. This patch is called a9df523f76f43a38bd53b4232b9cfd4c16869e71. Upgrading the affected component is advised.

CVSS v3
5.3
EG Score
5.3MEDIUMmedium confidence
EG Risk
39
EG Risk 39/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity53% × 45%
Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 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
0.5%
EPSS %ILE
40th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.

EG Severity
5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

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.

The score's inputs: 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

September 28, 2026

Last Modified

October 1, 2026

Advisory Details (3)

Auto-updated Sep 28, 2026
Patch available. Sources: github_commit, github_release.
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

Mongoose 7.22

Patch available: cesanta/mongoose 7.22

https://github.com/cesanta/mongoose/releases/tag/7.22
GitHub commit Patch Available

commit a9df523f76f4 (cesanta/mongoose)

Patch available: cesanta/mongoose 7.22 (contains commit a9df523f76f4)

https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71

Vendor Advisories for CVE-2026-101003(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(2)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 53× 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.

  1. 2026-11-02 16:43 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  2. 2026-11-01 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  3. 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  4. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  5. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.5% · 40th percentile
  6. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  7. 2026-10-28 06:32 UTCEG score recompute
  8. 2026-10-28 06:32 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  9. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  10. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  11. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  12. 2026-10-25 15:57 UTCEG score recompute
  13. 2026-10-24 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  14. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  15. 2026-10-23 09:52 UTCEG score recompute
  16. 2026-10-23 09:52 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  17. 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  18. 2026-10-21 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  19. 2026-10-20 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  20. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  21. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  22. 2026-10-18 05:11 UTCEG score recompute
  23. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  24. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  25. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
Show 53 more
  1. 2026-10-14 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  2. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  3. 2026-10-12 16:41 UTCEG score recompute
  4. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  5. 2026-10-12 04:48 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  6. 2026-10-11 20:16 UTCEG score recompute
  7. 2026-10-11 18:28 UTCEG score recompute
  8. 2026-10-11 15:02 UTCEG score recompute
  9. 2026-10-11 13:47 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  10. 2026-10-11 03:30 UTCEG score recompute
  11. 2026-10-11 03:30 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  12. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  13. 2026-10-10 01:54 UTCEG score recompute
  14. 2026-10-10 01:53 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  15. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  16. 2026-10-09 00:35 UTCEG score recompute
  17. 2026-10-09 00:35 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  18. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  19. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  20. 2026-10-07 23:18 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  21. 2026-10-06 22:00 UTCEG score recompute
  22. 2026-10-06 22:00 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  23. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  24. 2026-10-05 20:42 UTCEG score recompute
  25. 2026-10-05 20:42 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  26. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  27. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  28. 2026-10-04 19:25 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  29. 2026-10-03 18:07 UTCEG score recompute
  30. 2026-10-03 18:06 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  31. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  32. 2026-10-02 16:42 UTCEG score recompute
  33. 2026-10-02 16:42 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  34. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  35. 2026-10-01 15:25 UTCEG score recompute
  36. 2026-10-01 15:24 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  37. 2026-10-01 15:22 UTCNVD updateCVSS v4 → 5.5
  38. 2026-10-01 14:22 UTCEG score recompute
  39. 2026-10-01 14:22 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  40. 2026-10-01 14:20 UTCMITRE cvelistV5CVSS v4 → 6.9
  41. 2026-09-30 18:05 UTCEG score recompute
  42. 2026-09-30 18:04 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  43. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  44. 2026-09-29 16:46 UTCEG score recompute
  45. 2026-09-29 16:46 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  46. 2026-09-29 15:20 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  47. 2026-09-28 15:28 UTCEG score recompute
  48. 2026-09-28 15:28 UTCGHSA enrichmentGHSA-g7gm-388f-77vf · GitHub CVSS 5.3
  49. 2026-09-28 13:50 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  50. 2026-09-28 06:24 UTCEG score recompute
  51. 2026-09-28 06:24 UTCNVD updateCVSS v4 → 5.5
  52. 2026-09-28 05:47 UTCEG score recomputeFirst assessed: 5.3 MEDIUM
  53. 2026-09-28 05:47 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-101003?
CVE-2026-101003 is a medium-severity vulnerability; its CVE record was published on September 28, 2026. A weakness has been identified in Cesanta Mongoose up to 7.21. Affected by this vulnerability is the function fn of the file tutorials/mqtt/mqtt-server/main.c of the component MQTT Broker. Executing a manipulation can lead to stack-based buffer overflow. The attack can be launched remotely. The…
When was the CVE record for CVE-2026-101003 published?
The CVE record for CVE-2026-101003 was published on September 28, 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 October 1, 2026; the record at its source may have been updated since.
Is CVE-2026-101003 actively exploited?
CVE-2026-101003 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (40th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-101003?
CVE-2026-101003 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-101003?
A fix for CVE-2026-101003 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-101003 are linked in the Vendor Advisories panel on this page.

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