Reference page — cumulative record through Saturday, October 3, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-77261

CVE-2026-77261HIGH

sooperset mcp-atlassian — MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   L   N  C  H  L  N    8.5   .0032   22.9     —

AFFECTED
  Product        Versions    Fixed
  mcp-atlassian  < 0.22.0 –  —

TIMELINE
  Aug 20  Reserved by GitHub_M
  Sep 22  Published (CNA: GitHub_M)
  Sep 25  EXPLOIT PUBLISHED — CVE-2026-77261 (sooperset mcp-atlassian). Public exploit reference added.
  Sep 25  RESCORED — CVE-2026-77261 (sooperset mcp-atlassian). CVSS 7.1 → 8.5 (NVD).

CWE-918 · CNA: GitHub_M · CVSS v3.1 · 4 references · NVD status: Analyzed

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, _make_ssrf_safe_hook is omitted from JiraFetcher and ConfluenceFetcher sessions created through the basic-auth and oauth_pat branches. If an attacker-controlled or compromised configured Atlassian instance returns a redirect to an internal address, those sessions can follow the redirect without revalidating its destination. This issue is fixed in version 0.22.0.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
August 20, 2026	Reserved	Reserved by GitHub_M
September 22, 2026	Published	Published (CNA: GitHub_M)
September 25, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2026-77261 (sooperset mcp-atlassian). Public exploit reference added.
September 25, 2026	RESCORED	RESCORED — CVE-2026-77261 (sooperset mcp-atlassian). CVSS 7.1 → 8.5 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
sooperset	mcp-atlassian	—	< 0.22.0	—

Weaknesses

CWE-918

References (4)

https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 [Patch]
https://github.com/sooperset/mcp-atlassian/pull/1448 [Patch]
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 [Release Notes]
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6529-c226-h328 [Exploit, Vendor Advisory]

Authoritative record: CVE-2026-77261 at cve.org

Vendors: sooperset

Weaknesses: CWE-918

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-77261 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Saturday, October 3, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.