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.
CVE-2026-77357
HIGHPre-NVD 8.78.7
EchelonGraph scoreLOW confidence
This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 8.7Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.7
- EG Score
- 8.7(low)
- EG Risk
- 44(Track)EG Risk 44/100SSVC: 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 computedSeverity87% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
August 25, 2026
Last Modified
August 25, 2026
Advisory Details (3)
Auto-updated Aug 25, 2026Patch 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/v1.3.3github_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/2b8e7f2c349c9e2eec202f46b07bada83061ce2dgithub 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-83mxWeakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× 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.
- 2026-08-25 21:27 UTCEG score recompute
- 2026-08-25 20:55 UTCEG score recompute
- 2026-08-25 20:54 UTCMITRE cvelistV5first tracked
Frequently asked(4)
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. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-77357?
CVE-2026-77357 has a CVSS v3 base score of 8.7 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
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
Explore the affected products and dependency analysis for CVE-2026-77357
Is Your Infrastructure Affected by CVE-2026-77357?
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