CVE-2026-73259

MEDIUMPre-NVD 5.45.4
EchelonGraph scoreMEDIUM confidence

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

This medium-severity CVE scores 5.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (33rd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
5.4EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.4Exploit: No code on recordExposed 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 send a crafted percent-encoded request path to a deployment using MG_ENABLE_DIRLIST and persuade a user to visit it. The mg_http_serve_dir() and listdir() path in src/http.c places the decoded request URI into the title and h1 elements without HTML entity encoding. The resulting reflected cross-site scripting executes in the Mongoose origin and can expose session data or perform actions as the victim. This issue is fixed in version 7.22.

CVSS v3
5.4
EG Score
5.4MEDIUMmedium confidence
EG Risk
40
EG Risk 40/100

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)
Severity54% × 45%
The EG Score, 5.4 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (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.
EPSS PROB
0.4%
EPSS %ILE
33rd
KEV
Not listed

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

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (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

August 20, 2026

Last Modified

September 29, 2026

Advisory Details (4)

Auto-updated Aug 20, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
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 pull request Patch Available

assorted patches

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

https://github.com/cesanta/mongoose/pull/3611
GitHub advisoryMentions a patch (unverified)

Reflected XSS via decoded URI in directory listing render · Advisory · cesanta/mongoose · GitHub

https://github.com/cesanta/mongoose/security/advisories/GHSA-9cwm-487w-h25w

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 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.

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. 2 repeat rows among the latest 87 are merged into the row they repeat.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  2. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  3. 2026-10-12 15:41 UTCEG score recompute
  4. 2026-10-11 19:26 UTCEG score recompute
  5. 2026-10-11 16:42 UTCEG score recompute
  6. 2026-10-11 14:02 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  10. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  12. 2026-10-07 10:06 UTCEG score recompute
  13. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  14. 2026-10-06 07:52 UTCEG score recompute
  15. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  16. 2026-10-05 05:00 UTCEG score recompute
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  18. 2026-10-04 02:39 UTCEG score recompute
  19. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  20. 2026-10-03 00:40 UTCEG score recompute
  21. 2026-10-01 22:44 UTCEG score recompute
  22. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  23. 2026-09-30 20:31 UTCEG score recompute
  24. 2026-09-29 16:05 UTCEG score recompute
  25. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
Show 60 more
  1. 2026-09-29 06:50 UTCEG score recompute
  2. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  3. 2026-09-28 04:56 UTCEG score recompute
  4. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  5. 2026-09-27 03:01 UTCEG score recompute
  6. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  7. 2026-09-25 01:52 UTCEG score recompute
  8. 2026-09-23 23:58 UTCEG score recompute
  9. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  10. 2026-09-22 22:03 UTCEG score recompute
  11. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  12. 2026-09-21 20:08 UTCEG score recompute
  13. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  14. 2026-09-19 16:04 UTCEG score recompute
  15. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  16. 2026-09-18 13:58 UTCEG score recompute
  17. 2026-09-17 11:57 UTCEG score recompute
  18. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  19. 2026-09-16 10:02 UTCEG score recompute
  20. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  21. 2026-09-15 08:07 UTCEG score recompute
  22. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  23. 2026-09-14 06:12 UTCEG score recompute
  24. 2026-09-13 04:18 UTCEG score recompute
  25. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  26. 2026-09-12 02:23 UTCEG score recompute
  27. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  28. 2026-09-11 00:28 UTCEG score recompute
  29. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  30. 2026-09-09 01:56 UTCEG score recompute
  31. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  32. 2026-09-07 06:58 UTCEG score recompute
  33. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  34. 2026-09-06 04:58 UTCEG score recompute
  35. 2026-09-05 03:04 UTCEG score recompute
  36. 2026-09-02 23:09 UTCEG score recompute
  37. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  38. 2026-09-01 21:12 UTCEG score recompute
  39. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  40. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  41. 2026-08-31 19:04 UTCEG score recompute
  42. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  43. 2026-08-30 13:39 UTCEG score recompute
  44. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  45. 2026-08-29 11:42 UTCEG score recompute
  46. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  47. 2026-08-28 09:47 UTCEG score recompute
  48. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  49. 2026-08-27 07:52 UTCEG score recompute
  50. 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  51. 2026-08-26 05:57 UTCEG score recompute
  52. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  53. 2026-08-25 04:02 UTCEG score recompute
  54. 2026-08-24 02:07 UTCEG score recompute
  55. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  56. 2026-08-23 00:10 UTCEG score recompute
  57. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  58. 2026-08-20 18:17 UTCEG score recompute
  59. 2026-08-20 17:46 UTCEG score recomputeFirst assessed: 5.4 MEDIUM
  60. 2026-08-20 17:46 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-73259?
CVE-2026-73259 is a medium-severity vulnerability; its CVE record was published on August 20, 2026. Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can send a crafted percent-encoded request path to a deployment using MGENABLEDIRLIST and persuade a user to visit it. The mghttpserve_dir() and listdir() path in src/http.c places the decoded request URI into…
When was the CVE record for CVE-2026-73259 published?
The CVE record for CVE-2026-73259 was published on August 20, 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 September 29, 2026; the record at its source may have been updated since.
Is CVE-2026-73259 actively exploited?
CVE-2026-73259 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (33rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-73259?
CVE-2026-73259 has a CVSS base score of 5.4 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-73259?
A fix for CVE-2026-73259 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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