CVE-2026-77261
MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches
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.
INFO
Published Date :
Sept. 22, 2026, 6:17 p.m.
Last Modified :
Sept. 25, 2026, 5:36 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-77261
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update MCP Atlassian to version 0.22.0.
- Ensure _make_ssrf_safe_hook is correctly configured.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-77261.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-77261 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-77261
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-77261 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-77261 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 25, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:* versions up to (excluding) 0.22.0 Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/pull/1448 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6529-c226-h328 Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 23, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-77261', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-22T19:07:42.566871Z'} -
New CVE Received by [email protected]
Sep. 22, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N Added CWE CWE-918 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/77xxx/CVE-2026-77261.json">CVE-2026-77261</a> Added Reference https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 Added Reference https://github.com/sooperset/mcp-atlassian/pull/1448 Added Reference https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 Added Reference https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6529-c226-h328