CVE-2026-73258

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (37th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 6.5Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can place a lone carriage return or line feed in multipart input processed by mg_http_next_multipart() in src/http.c. The loops comparing s[b] and s[b + 1], and s[h2] and s[h2 + 1], use an incorrect AND condition and stop when either character resembles part of a CRLF terminator. This truncates headers, filenames, or boundaries and can cause an application to accept dangerous content after seeing a misleading Content-Type value. This issue is fixed in version 7.22.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
60
EG Risk 60/100CISA SSVC

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
Severity65% × 45%
Exploitation40% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
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
37th
KEV
Not listed

CISA SSVCTrack 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 public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 29, 2026

Advisory Details (4)

Auto-updated Aug 20, 2026
🔬 Proof of concept available. Patch available. Sources: github_pr, github_commit, github_release, github.
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
github_pr Patch Available

assorted patches

Patch available: cesanta/mongoose 7.22 (PR #3611 merged 2026-06-23)

https://github.com/cesanta/mongoose/pull/3611
githubMentions a patch (unverified)🟡 PoC Available

Multipart boundary/header scan logic error in mg_http_next_multipart · Advisory · cesanta/mongoose · GitHub

https://github.com/cesanta/mongoose/security/advisories/GHSA-cc55-8v3r-59p8

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 / 47× 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. 2026-10-10 20:00 UTCEPSS rescore
  2. 2026-10-09 20:07 UTCEPSS rescore
  3. 2026-10-08 17:13 UTCEPSS rescore
  4. 2026-10-07 23:48 UTCEPSS rescore
  5. 2026-10-07 10:06 UTCEG score recompute
  6. 2026-10-06 15:18 UTCEPSS rescore
  7. 2026-10-06 07:52 UTCEG score recompute
  8. 2026-10-05 17:43 UTCEPSS rescore
  9. 2026-10-05 05:00 UTCEG score recompute
  10. 2026-10-04 23:22 UTCEPSS rescore
  11. 2026-10-04 02:39 UTCEG score recompute
  12. 2026-10-03 14:26 UTCEPSS rescore
  13. 2026-10-03 00:40 UTCEG score recompute
  14. 2026-10-01 22:44 UTCEG score recompute
  15. 2026-10-01 19:50 UTCEPSS rescore
  16. 2026-09-30 20:31 UTCEG score recompute
  17. 2026-09-29 16:05 UTCEG score recompute
  18. 2026-09-29 15:24 UTCEPSS rescore
  19. 2026-09-29 05:42 UTCEG score recompute
  20. 2026-09-28 13:52 UTCEPSS rescore
  21. 2026-09-28 04:22 UTCEG score recompute
  22. 2026-09-27 13:48 UTCEPSS rescore
  23. 2026-09-27 03:02 UTCEG score recompute
  24. 2026-09-26 15:59 UTCEPSS rescore
  25. 2026-09-24 19:07 UTCEG score recompute
Show 61 more
  1. 2026-09-23 17:54 UTCEPSS rescore
  2. 2026-09-23 16:35 UTCEG score recompute
  3. 2026-09-22 15:15 UTCEG score recompute
  4. 2026-09-21 21:09 UTCEPSS rescore
  5. 2026-09-21 13:56 UTCEG score recompute
  6. 2026-09-20 20:16 UTCEPSS rescore
  7. 2026-09-20 12:37 UTCEG score recompute
  8. 2026-09-19 11:07 UTCEG score recompute
  9. 2026-09-18 19:28 UTCEPSS rescore
  10. 2026-09-18 09:48 UTCEG score recompute
  11. 2026-09-17 08:28 UTCEG score recompute
  12. 2026-09-16 14:08 UTCEPSS rescore
  13. 2026-09-16 07:06 UTCEG score recompute
  14. 2026-09-16 05:15 UTCEPSS rescore
  15. 2026-09-15 05:46 UTCEG score recompute
  16. 2026-09-15 03:12 UTCEPSS rescore
  17. 2026-09-14 04:17 UTCEG score recompute
  18. 2026-09-13 02:58 UTCEG score recompute
  19. 2026-09-12 15:02 UTCEPSS rescore
  20. 2026-09-12 01:38 UTCEG score recompute
  21. 2026-09-11 14:53 UTCEPSS rescore
  22. 2026-09-11 00:18 UTCEG score recompute
  23. 2026-09-10 09:35 UTCEPSS rescore
  24. 2026-09-09 01:56 UTCEG score recompute
  25. 2026-09-08 22:01 UTCEPSS rescore
  26. 2026-09-07 18:31 UTCEG score recompute
  27. 2026-09-06 17:12 UTCEG score recompute
  28. 2026-09-06 13:48 UTCEPSS rescore
  29. 2026-09-05 15:45 UTCEG score recompute
  30. 2026-09-04 14:26 UTCEG score recompute
  31. 2026-09-04 05:07 UTCEPSS rescore
  32. 2026-09-03 13:07 UTCEG score recompute
  33. 2026-09-02 14:12 UTCEPSS rescore
  34. 2026-09-02 11:42 UTCEG score recompute
  35. 2026-09-01 13:54 UTCEPSS rescore
  36. 2026-09-01 10:19 UTCEG score recompute
  37. 2026-09-01 04:40 UTCEPSS rescore
  38. 2026-09-01 04:40 UTCEPSS rescore
  39. 2026-08-31 08:55 UTCEG score recompute
  40. 2026-08-30 19:18 UTCEPSS rescore
  41. 2026-08-30 19:17 UTCEPSS rescore
  42. 2026-08-30 07:23 UTCEG score recompute
  43. 2026-08-30 01:22 UTCEPSS rescore
  44. 2026-08-29 06:00 UTCEG score recompute
  45. 2026-08-28 21:42 UTCEPSS rescore
  46. 2026-08-28 04:40 UTCEG score recompute
  47. 2026-08-27 14:25 UTCEPSS rescore
  48. 2026-08-27 03:19 UTCEG score recompute
  49. 2026-08-26 14:47 UTCEPSS rescore
  50. 2026-08-26 01:58 UTCEG score recompute
  51. 2026-08-25 13:49 UTCEPSS rescore
  52. 2026-08-25 00:38 UTCEG score recompute
  53. 2026-08-23 23:16 UTCEG score recompute
  54. 2026-08-23 00:19 UTCEPSS rescore
  55. 2026-08-22 21:57 UTCEG score recompute
  56. 2026-08-21 23:49 UTCEPSS rescore
  57. 2026-08-20 19:18 UTCEG score recompute
  58. 2026-08-20 18:52 UTCEG score recompute
  59. 2026-08-20 18:17 UTCEG score recompute
  60. 2026-08-20 17:46 UTCEG score recompute
  61. 2026-08-20 17:46 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-73258?
CVE-2026-73258 is a medium vulnerability published on August 20, 2026. Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can place a lone carriage return or line feed in multipart input processed by mghttpnext_multipart() in src/http.c. The loops comparing s[b] and s[b + 1], and s[h2] and s[h2 + 1], use an incorrect AND condition…
When was CVE-2026-73258 disclosed?
CVE-2026-73258 was first published on August 20, 2026, with the most recent update on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73258 actively exploited?
CVE-2026-73258 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (37th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73258?
CVE-2026-73258 has a CVSS base score of 6.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73258?
A fix for CVE-2026-73258 is available: update to the fixed version the vendor names in its advisory.

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