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: 0.3%, top 78% 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
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%CVSS: 9.1Exploit: Elevated riskExposed: 0

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

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
9.1(medium)
EG Risk
57(Track*)
EG Risk 57/100SSVC: 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
Severity91% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

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.
github Patch Available🟡 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 rangeFixed inDependents
praisonai0.0.1 ... 4.6.9 (748 versions)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 / 48× 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. 2026-09-18 21:34 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 21:08 UTCEG score recompute
  4. 2026-09-17 19:31 UTCEPSS rescore
  5. 2026-09-16 14:56 UTCEG score recompute
  6. 2026-09-16 14:08 UTCEPSS rescore
  7. 2026-09-16 07:16 UTCEG score recompute
  8. 2026-09-16 05:15 UTCEPSS rescore
  9. 2026-09-15 04:18 UTCEG score recompute
  10. 2026-09-15 03:11 UTCEPSS rescore
  11. 2026-09-13 17:53 UTCEG score recompute
  12. 2026-09-13 16:47 UTCEPSS rescore
  13. 2026-09-12 15:05 UTCEG score recompute
  14. 2026-09-11 15:50 UTCEG score recompute
  15. 2026-09-11 14:53 UTCEPSS rescore
  16. 2026-09-11 12:00 UTCEG score recompute
  17. 2026-09-10 12:32 UTCEG score recompute
  18. 2026-09-10 09:35 UTCEPSS rescore
  19. 2026-09-09 01:14 UTCEG score recompute
  20. 2026-09-08 22:01 UTCEPSS rescore
  21. 2026-09-07 19:06 UTCEG score recompute
  22. 2026-09-07 16:01 UTCEPSS rescore
  23. 2026-09-06 14:03 UTCEG score recompute
  24. 2026-09-06 13:47 UTCEPSS rescore
  25. 2026-09-05 18:55 UTCEG score recompute
Show 23 more
  1. 2026-09-04 15:27 UTCEG score recompute
  2. 2026-09-04 07:42 UTCEG score recompute
  3. 2026-09-04 05:06 UTCEPSS rescore
  4. 2026-09-02 16:05 UTCEG score recompute
  5. 2026-09-02 14:12 UTCEPSS rescore
  6. 2026-09-01 17:07 UTCEG score recompute
  7. 2026-09-01 13:54 UTCEPSS rescore
  8. 2026-09-01 05:14 UTCEG score recompute
  9. 2026-09-01 04:40 UTCEPSS rescore
  10. 2026-08-30 21:34 UTCEG score recompute
  11. 2026-08-30 19:17 UTCEPSS rescore
  12. 2026-08-30 02:23 UTCEG score recompute
  13. 2026-08-30 01:22 UTCEPSS rescore
  14. 2026-08-28 23:28 UTCEG score recompute
  15. 2026-08-28 22:51 UTCEG score recompute
  16. 2026-08-28 21:41 UTCEPSS rescore
  17. 2026-08-27 14:27 UTCEG score recompute
  18. 2026-08-27 14:25 UTCEPSS rescore
  19. 2026-08-26 15:25 UTCEG score recompute
  20. 2026-08-26 14:46 UTCEPSS rescore
  21. 2026-08-25 16:24 UTCEG score recompute
  22. 2026-08-25 15:30 UTCEG score recompute
  23. 2026-08-25 15:29 UTCMITRE cvelistV5first tracked

Related CVEs(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 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-2026-55536 actively exploited?
CVE-2026-55536 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 78.1% of all scored CVEs.
What is the CVSS score of CVE-2026-55536?
CVE-2026-55536 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-55536?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55536, 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

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

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