CVE-2026-55536

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (42nd percentile of EPSS-scored CVEs). 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
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 9.1Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, Browser Server _handle_connection() checks Chrome extension origins with re.match() and the unanchored expression chrome-extension://[a-z0-9]{32}. Extra trailing characters pass before websocket.accept(), allowing start_session commands and unauthorized browser automation. This issue is fixed in version 4.6.58.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
57
EG Risk 57/100CISA SSVC

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
Severity91% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
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
42nd
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

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 no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 25, 2026

Last Modified

September 9, 2026

Advisory Details (3)

Auto-updated Sep 15, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github, github_commit.
githubMentions a patch (unverified)🟡 PoC Available

Browser Server WebSocket origin validation bypass via unanchored regex (patch bypass of CVE-2026-40289 / GHSA-8x8f-54wf-vv92) · Advisory · MervinPraison/PraisonAI · GitHub

https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-6g6r-q6gw-w8fg
github_release Patch Available

PraisonAI v4.6.58

Patch available: MervinPraison/PraisonAI v4.6.58

https://github.com/MervinPraison/PraisonAI/releases/tag/v4.6.58
github_commit Patch Available

commit 2f9677abb2ea (MervinPraison/PraisonAI)

Patch available: MervinPraison/PraisonAI v4.6.144 (contains commit 2f9677abb2ea)

https://github.com/MervinPraison/PraisonAI/commit/2f9677abb2ea68eab864ee8b6a828fd0141612e1

Vendor Advisories for CVE-2026-55536(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
praisonai0.0.1 ... 4.6.9 (748 versions)
  • every version up to 4.6.58: fixed in 4.6.58
—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 55× 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. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-09 04:23 UTCEG score recompute
  3. 2026-10-08 17:12 UTCEPSS rescore
  4. 2026-10-08 03:16 UTCEG score recompute
  5. 2026-10-07 23:48 UTCEPSS rescore
  6. 2026-10-06 16:09 UTCEG score recompute
  7. 2026-10-06 15:18 UTCEPSS rescore
  8. 2026-10-05 20:50 UTCEG score recompute
  9. 2026-10-05 17:43 UTCEPSS rescore
  10. 2026-10-04 23:39 UTCEG score recompute
  11. 2026-10-04 23:22 UTCEPSS rescore
  12. 2026-10-03 16:26 UTCEG score recompute
  13. 2026-10-03 14:26 UTCEPSS rescore
  14. 2026-10-02 18:53 UTCEG score recompute
  15. 2026-10-02 17:56 UTCEPSS rescore
  16. 2026-10-01 20:05 UTCEG score recompute
  17. 2026-10-01 19:50 UTCEPSS rescore
  18. 2026-09-30 20:15 UTCEG score recompute
  19. 2026-09-30 15:03 UTCEPSS rescore
  20. 2026-09-30 06:47 UTCEG score recompute
  21. 2026-09-29 15:22 UTCEPSS rescore
  22. 2026-09-29 01:35 UTCEG score recompute
  23. 2026-09-28 21:29 UTCEG score recompute
  24. 2026-09-28 13:51 UTCEPSS rescore
  25. 2026-09-27 14:31 UTCEG score recompute
Show 60 more
  1. 2026-09-27 13:48 UTCEPSS rescore
  2. 2026-09-26 22:05 UTCEG score recompute
  3. 2026-09-26 15:59 UTCEPSS rescore
  4. 2026-09-24 17:11 UTCEG score recompute
  5. 2026-09-24 14:04 UTCEPSS rescore
  6. 2026-09-23 18:08 UTCEG score recompute
  7. 2026-09-23 17:54 UTCEPSS rescore
  8. 2026-09-22 19:04 UTCEG score recompute
  9. 2026-09-21 23:06 UTCEG score recompute
  10. 2026-09-20 20:16 UTCEG score recompute
  11. 2026-09-20 20:16 UTCEPSS rescore
  12. 2026-09-19 16:42 UTCEG score recompute
  13. 2026-09-18 21:34 UTCEG score recompute
  14. 2026-09-18 19:28 UTCEPSS rescore
  15. 2026-09-17 21:08 UTCEG score recompute
  16. 2026-09-17 19:31 UTCEPSS rescore
  17. 2026-09-16 14:56 UTCEG score recompute
  18. 2026-09-16 14:08 UTCEPSS rescore
  19. 2026-09-16 07:16 UTCEG score recompute
  20. 2026-09-16 05:15 UTCEPSS rescore
  21. 2026-09-15 04:18 UTCEG score recompute
  22. 2026-09-15 03:11 UTCEPSS rescore
  23. 2026-09-13 17:53 UTCEG score recompute
  24. 2026-09-13 16:47 UTCEPSS rescore
  25. 2026-09-12 15:05 UTCEG score recompute
  26. 2026-09-11 15:50 UTCEG score recompute
  27. 2026-09-11 14:53 UTCEPSS rescore
  28. 2026-09-11 12:00 UTCEG score recompute
  29. 2026-09-10 12:32 UTCEG score recompute
  30. 2026-09-10 09:35 UTCEPSS rescore
  31. 2026-09-09 01:14 UTCEG score recompute
  32. 2026-09-08 22:01 UTCEPSS rescore
  33. 2026-09-07 19:06 UTCEG score recompute
  34. 2026-09-07 16:01 UTCEPSS rescore
  35. 2026-09-06 14:03 UTCEG score recompute
  36. 2026-09-06 13:47 UTCEPSS rescore
  37. 2026-09-05 18:55 UTCEG score recompute
  38. 2026-09-04 15:27 UTCEG score recompute
  39. 2026-09-04 07:42 UTCEG score recompute
  40. 2026-09-04 05:06 UTCEPSS rescore
  41. 2026-09-02 16:05 UTCEG score recompute
  42. 2026-09-02 14:12 UTCEPSS rescore
  43. 2026-09-01 17:07 UTCEG score recompute
  44. 2026-09-01 13:54 UTCEPSS rescore
  45. 2026-09-01 05:14 UTCEG score recompute
  46. 2026-09-01 04:40 UTCEPSS rescore
  47. 2026-08-30 21:34 UTCEG score recompute
  48. 2026-08-30 19:17 UTCEPSS rescore
  49. 2026-08-30 02:23 UTCEG score recompute
  50. 2026-08-30 01:22 UTCEPSS rescore
  51. 2026-08-28 23:28 UTCEG score recompute
  52. 2026-08-28 22:51 UTCEG score recompute
  53. 2026-08-28 21:41 UTCEPSS rescore
  54. 2026-08-27 14:27 UTCEG score recompute
  55. 2026-08-27 14:25 UTCEPSS rescore
  56. 2026-08-26 15:25 UTCEG score recompute
  57. 2026-08-26 14:46 UTCEPSS rescore
  58. 2026-08-25 16:24 UTCEG score recompute
  59. 2026-08-25 15:30 UTCEG score recompute
  60. 2026-08-25 15:29 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-55536?
CVE-2026-55536 is a critical vulnerability published on August 25, 2026. PraisonAI is a multi-agent teams system. Prior to praisonai 4.6.58, Browser Server handleconnection() checks Chrome extension origins with re.match() and the unanchored expression chrome-extension://[a-z0-9]{32}. Extra trailing characters pass before websocket.accept(), allowing start_session…
When was CVE-2026-55536 disclosed?
CVE-2026-55536 was first published 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-2026-55536 actively exploited?
CVE-2026-55536 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (42nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55536?
CVE-2026-55536 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55536?
A fix for CVE-2026-55536 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55536 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55536

Explore →

Is Your Infrastructure Affected by CVE-2026-55536?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs