CVE-2026-77357

HIGHPre-NVD 8.78.7
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (45th 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-2026-66114 (ENISA EUVD)Source: ENISA EUVD

8.7EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (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: 0.5%CVSS: 8.7Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

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
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
70
EG Risk 70/100

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)
Severity87% × 45%
Impact severity (EG Severity): CVSS 8.7 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.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
45th
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 (8.7): severity, escalated by confirmed exploitation. This CVE's 8.7 is its impact severity (EG Severity), not escalated.

EG Severity
8.7 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-09). 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; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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 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 advisoryMentions a patch (unverified)

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 7× in last 7d / 30× 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 → 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 131 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 31 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 0.5% · 45th percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  4. 2026-11-10 16:45 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  5. 2026-11-10 10:58 UTCEchelonGraph re-scored
  6. 2026-11-09 16:36 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  7. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  8. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  9. 2026-11-06 16:39 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  10. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  11. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  12. 2026-11-03 16:49 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  13. 2026-11-03 15:50 UTCEchelonGraph re-scored
  14. 2026-11-02 16:46 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  15. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  16. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  17. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  18. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  19. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  20. 2026-10-27 19:21 UTCEchelonGraph re-scored
  21. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  22. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  23. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  24. 2026-10-25 14:01 UTCEchelonGraph re-scored
  25. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
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  1. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  2. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  3. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  4. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  5. 2026-10-20 08:12 UTCEchelonGraph re-scored
  6. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  7. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  8. 2026-10-18 03:12 UTCEchelonGraph re-scored
  9. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  10. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  11. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  13. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  14. 2026-10-13 06:58 UTCEchelonGraph re-scored
  15. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  16. 2026-10-12 15:37 UTCEchelonGraph re-scored
  17. 2026-10-11 19:23 UTCEchelonGraph re-scored
  18. 2026-10-11 16:39 UTCEchelonGraph re-scored
  19. 2026-10-11 13:58 UTCEchelonGraph re-scored
  20. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  21. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  22. 2026-10-10 11:11 UTCEchelonGraph re-scored
  23. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  24. 2026-10-09 03:42 UTCEchelonGraph re-scored
  25. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  26. 2026-10-08 02:17 UTCEchelonGraph re-scored
  27. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  28. 2026-10-06 16:01 UTCEchelonGraph re-scored
  29. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  30. 2026-10-06 01:51 UTCEchelonGraph re-scored
  31. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  32. 2026-10-05 09:03 UTCEchelonGraph re-scored
  33. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
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  35. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  36. 2026-10-03 02:04 UTCEchelonGraph re-scored
  37. 2026-10-01 22:40 UTCEchelonGraph re-scored
  38. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  39. 2026-09-30 20:09 UTCEchelonGraph re-scored
  40. 2026-09-29 16:09 UTCEchelonGraph re-scored
  41. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  42. 2026-09-29 02:30 UTCEchelonGraph re-scored
  43. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  44. 2026-09-28 00:07 UTCEchelonGraph re-scored
  45. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  46. 2026-09-26 21:38 UTCEchelonGraph re-scored
  47. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  48. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  49. 2026-09-24 18:51 UTCEchelonGraph re-scored
  50. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
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  52. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  53. 2026-09-23 03:17 UTCEchelonGraph re-scored
  54. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  55. 2026-09-22 00:54 UTCEchelonGraph re-scored
  56. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  57. 2026-09-20 22:32 UTCEchelonGraph re-scored
  58. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  59. 2026-09-19 20:02 UTCEchelonGraph re-scored
  60. 2026-09-19 06:51 UTCEchelonGraph re-scored
  61. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  62. 2026-09-18 04:19 UTCEchelonGraph re-scored
  63. 2026-09-17 01:57 UTCEchelonGraph re-scored
  64. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  65. 2026-09-16 12:45 UTCEchelonGraph re-scored
  66. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  67. 2026-09-15 09:43 UTCEchelonGraph re-scored
  68. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  69. 2026-09-13 18:08 UTCEchelonGraph re-scored
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  71. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  72. 2026-09-12 02:33 UTCEchelonGraph re-scored
  73. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
  74. 2026-09-11 13:20 UTCEchelonGraph re-scored
  75. 2026-09-10 10:24 UTCEchelonGraph re-scored

Frequently asked(5)

What is CVE-2026-77357?
CVE-2026-77357 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-77357 published?
The CVE record for CVE-2026-77357 was published on August 25, 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 9, 2026; the record at its source may have been updated since.
Is CVE-2026-77357 actively exploited?
CVE-2026-77357 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (45th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77357?
CVE-2026-77357 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77357?
A fix for CVE-2026-77357 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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