CVE-2026-53649: Joro: Unauthenticated Cross-Origin Plugin Upload Leads to RCE

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.3%, percentile 25: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 25% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
• Only applies if your dependency tree includes github.com/BishopFox/joro (Go) < 0.0.0-20260601151442-5c0ca35db828, fixed in 0.0.0-20260601151442-5c0ca35db828. Check your lockfile, including transitive dependencies.

What it is

Joro is a web exploitation framework. Prior to version 1.1.1, Joro's default proxy mode exposes a local API on 127.0.0.1:9090 that performs no authentication and applies a wildcard CORS policy. Because plugin uploads use the CORS-safelisted multipart/form-data content type, cross-origin JavaScript on any page the operator visits can reach privileged endpoints - including uploading a native plugin and triggering a restart - directly through the operator's browser, with no preflight or credentials. Since plugins execute on load, this yields unauthenticated remote code execution as the operator's user from a single page visit. This issue has been patched in version 1.1.1.

From the GitHub advisory

Unauthenticated Cross-Origin Plugin Upload Leads to RCE (Joro ≤ v1.1.0)

Severity: Critical CVSS v3.1: 9.6 (AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H) Affected versions: Joro ≤ v1.1.0, proxy mode (default), Linux/macOS Reporter: cstover Date: 2026-05-27

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Summary

Joro's default proxy mode (in versions

Weakness type: CWE-306, CWE-352, CWE-434, CWE-942.

Product: github.com/BishopFox/joro (Go) · Assigned by: GitHub_M · Published: 2026-09-02

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.33% probability of exploitation activity in the next 30 days; percentile 25.

Timeline

• 2026-07-08 — GitHub-reviewed advisory GHSA-xqhv-chqm-fhcc published (critical)
• 2026-09-02 — CVE record published by GitHub_M
• 2026-09-04 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-xqhv-chqm-fhcc github.com
2. CVE.org record CVE-2026-53649 cve.org
3. NVD entry CVE-2026-53649 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

Critical Go advisories · Today’s Security Digest