CVE-2026-73254

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 91% of all CVEs by exploit prediction. 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
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Mongoose is an embedded web server and network library. Prior to 7.22, an attacker who can create a file with an HTML payload in its name can trigger stored cross-site scripting when a user browses a directory served with MG_ENABLE_DIRLIST. The printdirentry() path called by listdir() in src/http.c URL-encodes the href but inserts the raw filesystem filename into the HTML link text. The browser executes the injected markup in the Mongoose origin, which can expose session data or permit actions as the victim. This issue is fixed in version 7.22.

CVSS v3
5.4
EG Score
5.4(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

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
Severity54% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
9%
KEV
Not listed

Published

August 20, 2026

Last Modified

August 21, 2026

Advisory Details (4)

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

Stored XSS via unescaped filenames in directory listing · Advisory · cesanta/mongoose · GitHub

https://github.com/cesanta/mongoose/security/advisories/GHSA-5g6j-m3pv-4f7g

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 16× 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. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 08:29 UTCEG score recompute
  3. 2026-08-28 21:42 UTCEPSS rescore
  4. 2026-08-27 10:36 UTCEG score recompute
  5. 2026-08-26 14:47 UTCEPSS rescore
  6. 2026-08-26 11:41 UTCEG score recompute
  7. 2026-08-25 13:49 UTCEPSS rescore
  8. 2026-08-25 12:49 UTCEG score recompute
  9. 2026-08-24 13:57 UTCEG score recompute
  10. 2026-08-22 16:13 UTCEG score recompute
  11. 2026-08-21 23:49 UTCEPSS rescore
  12. 2026-08-21 17:21 UTCEG score recompute
  13. 2026-08-21 16:29 UTCEG score recompute
  14. 2026-08-20 18:17 UTCEG score recompute
  15. 2026-08-20 17:46 UTCEG score recompute
  16. 2026-08-20 17:46 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-73254?
CVE-2026-73254 is a medium vulnerability published on August 20, 2026. Mongoose is an embedded web server and network library. Prior to 7.22, an attacker who can create a file with an HTML payload in its name can trigger stored cross-site scripting when a user browses a directory served with MGENABLEDIRLIST. The printdirentry() path called by listdir() in src/http.c…
When was CVE-2026-73254 disclosed?
CVE-2026-73254 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on August 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-73254 actively exploited?
CVE-2026-73254 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 91.2% of all scored CVEs.
What is the CVSS score of CVE-2026-73254?
CVE-2026-73254 has a CVSS v3 base score of 5.4 (NVD).
How do I remediate CVE-2026-73254?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-73254, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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