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% (35th 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

Also known asEUVD-2026-63498 (ENISA EUVD)Source: ENISA EUVD

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 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)
Severity54% × 45%
Impact severity (EG Severity): CVSS 5.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
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
35th
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 (5.4): severity, escalated by confirmed exploitation. This CVE's 5.4 is its impact severity (EG Severity), not escalated.

EG Severity
5.4 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). 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; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade 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; 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.

The score's inputs: 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

October 18, 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 7× in last 7d / 31× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 122 rows 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 22 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:57 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  4. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  5. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  6. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  7. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  8. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  9. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  10. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  13. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  14. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  16. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  17. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  18. 2026-10-28 04:25 UTCOSV refresh
  19. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  20. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  21. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  22. 2026-10-25 14:06 UTCEchelonGraph re-scored
  23. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  24. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  25. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
Show 75 more
  1. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  2. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  3. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  4. 2026-10-18 20:36 UTCEchelonGraph re-scored
  5. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  6. 2026-10-18 03:15 UTCEchelonGraph re-scored
  7. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  8. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  9. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  10. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  11. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  12. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  13. 2026-10-12 15:41 UTCEchelonGraph re-scored
  14. 2026-10-11 19:26 UTCEchelonGraph re-scored
  15. 2026-10-11 16:42 UTCEchelonGraph re-scored
  16. 2026-10-11 14:02 UTCEchelonGraph re-scored
  17. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  18. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  19. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 33rd percentile
  20. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  21. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  22. 2026-10-07 10:06 UTCEchelonGraph re-scored
  23. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  24. 2026-10-06 07:52 UTCEchelonGraph re-scored
  25. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  26. 2026-10-05 05:00 UTCEchelonGraph re-scored
  27. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  28. 2026-10-04 02:39 UTCEchelonGraph re-scored
  29. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  30. 2026-10-03 00:40 UTCEchelonGraph re-scored
  31. 2026-10-01 22:44 UTCEchelonGraph re-scored
  32. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  33. 2026-09-30 20:31 UTCEchelonGraph re-scored
  34. 2026-09-29 16:05 UTCEchelonGraph re-scored
  35. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  36. 2026-09-29 06:50 UTCEchelonGraph re-scored
  37. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  38. 2026-09-28 04:56 UTCEchelonGraph re-scored
  39. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  40. 2026-09-27 03:01 UTCEchelonGraph re-scored
  41. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 32nd percentile
  42. 2026-09-25 01:52 UTCEchelonGraph re-scored
  43. 2026-09-23 23:58 UTCEchelonGraph re-scored
  44. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  45. 2026-09-22 22:03 UTCEchelonGraph re-scored
  46. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  47. 2026-09-21 20:08 UTCEchelonGraph re-scored
  48. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  49. 2026-09-19 16:04 UTCEchelonGraph re-scored
  50. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  51. 2026-09-18 13:58 UTCEchelonGraph re-scored
  52. 2026-09-17 11:57 UTCEchelonGraph re-scored
  53. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  54. 2026-09-16 10:02 UTCEchelonGraph re-scored
  55. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  56. 2026-09-15 08:07 UTCEchelonGraph re-scored
  57. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  58. 2026-09-14 06:12 UTCEchelonGraph re-scored
  59. 2026-09-13 04:18 UTCEchelonGraph re-scored
  60. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  61. 2026-09-12 02:23 UTCEchelonGraph re-scored
  62. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 20th percentile
  63. 2026-09-11 00:28 UTCEchelonGraph re-scored
  64. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  65. 2026-09-09 01:56 UTCEchelonGraph re-scored
  66. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  67. 2026-09-07 06:58 UTCEchelonGraph re-scored
  68. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  69. 2026-09-06 04:58 UTCEchelonGraph re-scored
  70. 2026-09-05 03:04 UTCEchelonGraph re-scored
  71. 2026-09-02 23:09 UTCEchelonGraph re-scored
  72. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  73. 2026-09-01 21:12 UTCEchelonGraph re-scored
  74. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  75. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.2% · 13th percentile

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 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…
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 October 18, 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 (35th 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.

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