Skip to main content
VulnerabilityPublished

CVE-2026-77272: sooperset mcp-atlassian · Cross-site Scripting

Affects sooperset mcp-atlassianSource CVE Database V5

0
Compare

Not known to be exploited · CVSS 5.4 Medium : upgrade to 0.22.0 when convenient.

Data as of 5 Nov 2026, 23:24 UTC

CVSS 3.1 base score
5.4Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 0.22.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

What to do

Upgrade mcp-atlassian and sooperset/mcp-atlassian to 0.22.0.

Affected software

ProductAffectedFixed in
soopersetmcp-atlassianAffected
  • <0.22.0
Fixed in
  • 0.22.0
GitHubsooperset/mcp-atlassianpkg:github/sooperset/mcp-atlassianOther threatsAffected
  • <0.22.0
Fixed in
  • 0.22.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade sooperset mcp-atlassian to version 0.22.0 or later, where this XSS vulnerability is fixed. No other mitigation is indicated or required by the vendor advisory.

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth error query parameter is passed to CallbackHandler._send_response in oauth_setup.py and interpolated into an HTML page without escaping. A crafted authorization callback can inject markup or script that executes in the browser of a user completing the OAuth flow. This issue is fixed in version 0.22.0.

References

Community reviews

Loading reviews…