CVE-2026-77357

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 77% 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
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.7Exploit: Elevated riskExposed: 0

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

Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.3, applications running in debug mode expose a GET /hot-reload endpoint whose unbounded loop depends on the user-supplied counter parameter, allowing an unauthenticated attacker to hold worker threads with high counter values until the worker pool is exhausted and the server becomes unavailable. A single unauthenticated attacker can crash the Mesop server with minimal effort. Because the attack leverages worker exhaustion, the server remains unresponsive until it is manually restarted. This issue is fixed in version 1.3.3.

CVSS v3
8.7
EG Score
8.7(medium)
EG Risk
70(Attend)
EG Risk 70/100SSVC: Attend

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
Severity87% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

August 25, 2026

Last Modified

September 9, 2026

Advisory Details (3)

Auto-updated Aug 25, 2026
Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

v1.3.3

Patch available: mesop-dev/mesop v1.3.3

https://github.com/mesop-dev/mesop/releases/tag/v1.3.3
github_commit Patch Available

commit 2b8e7f2c349c (mesop-dev/mesop)

Patch available: mesop-dev/mesop v1.3.3 (contains commit 2b8e7f2c349c)

https://github.com/mesop-dev/mesop/commit/2b8e7f2c349c9e2eec202f46b07bada83061ce2d
github Patch Available

Denial of Service in /__hot-reload__ endpoint allows unauthenticated attacker to exhaust worker threads and crash the server · Advisory · mesop-dev/mesop · GitHub

https://github.com/mesop-dev/mesop/security/advisories/GHSA-8p72-497j-83mx

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 12× 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. 2026-09-19 06:51 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 04:19 UTCEG score recompute
  4. 2026-09-17 01:57 UTCEG score recompute
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 12:45 UTCEG score recompute
  7. 2026-09-16 05:15 UTCEPSS rescore
  8. 2026-09-15 09:43 UTCEG score recompute
  9. 2026-09-15 03:12 UTCEPSS rescore
  10. 2026-09-13 18:08 UTCEG score recompute
  11. 2026-09-12 15:45 UTCEG score recompute
  12. 2026-09-12 15:02 UTCEPSS rescore
  13. 2026-09-12 02:33 UTCEG score recompute
  14. 2026-09-11 14:53 UTCEPSS rescore
  15. 2026-09-11 13:20 UTCEG score recompute
  16. 2026-09-10 10:24 UTCEG score recompute
  17. 2026-09-10 09:35 UTCEPSS rescore
  18. 2026-09-09 01:05 UTCEG score recompute
  19. 2026-09-08 22:01 UTCEPSS rescore
  20. 2026-09-07 21:56 UTCEG score recompute
  21. 2026-09-06 19:24 UTCEG score recompute
  22. 2026-09-06 13:48 UTCEPSS rescore
  23. 2026-09-05 16:55 UTCEG score recompute
  24. 2026-09-04 14:31 UTCEG score recompute
  25. 2026-09-04 05:07 UTCEPSS rescore
Show 22 more
  1. 2026-09-02 22:54 UTCEG score recompute
  2. 2026-09-02 14:12 UTCEPSS rescore
  3. 2026-09-01 20:26 UTCEG score recompute
  4. 2026-09-01 13:54 UTCEPSS rescore
  5. 2026-09-01 07:15 UTCEG score recompute
  6. 2026-09-01 04:40 UTCEPSS rescore
  7. 2026-09-01 04:40 UTCEPSS rescore
  8. 2026-08-31 04:49 UTCEG score recompute
  9. 2026-08-30 19:18 UTCEPSS rescore
  10. 2026-08-30 19:17 UTCEPSS rescore
  11. 2026-08-30 02:26 UTCEG score recompute
  12. 2026-08-30 01:22 UTCEPSS rescore
  13. 2026-08-29 00:03 UTCEG score recompute
  14. 2026-08-28 21:42 UTCEPSS rescore
  15. 2026-08-27 18:07 UTCEG score recompute
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-26 15:43 UTCEG score recompute
  18. 2026-08-26 14:47 UTCEPSS rescore
  19. 2026-08-26 13:25 UTCEG score recompute
  20. 2026-08-25 21:27 UTCEG score recompute
  21. 2026-08-25 20:55 UTCEG score recompute
  22. 2026-08-25 20:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-77357?
CVE-2026-77357 is a high vulnerability published on August 25, 2026. Mesop is a Python-based UI framework that allows users to build web applications. Prior to 1.3.3, applications running in debug mode expose a GET /hot-reload endpoint whose unbounded loop depends on the user-supplied counter parameter, allowing an unauthenticated attacker to hold worker threads…
When was CVE-2026-77357 disclosed?
CVE-2026-77357 was first published in the National Vulnerability Database on August 25, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77357 actively exploited?
CVE-2026-77357 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 76.6% of all scored CVEs.
What is the CVSS score of CVE-2026-77357?
CVE-2026-77357 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-77357?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77357, 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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