CVE-2026-77251

HIGHPre-NVD 8.38.3
EchelonGraph scoreLOW confidence

This high-severity CVE scores 8.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
8.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 8.3Exploit: None knownExposed: 0

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

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, Jira search accepts a forbidden project clause because it checks only for the presence of project syntax, Confluence search uses an incomplete case-sensitive space check, and Jira board APIs omit project-filter enforcement. These paths expose issues, boards, or pages outside JIRA_PROJECTS_FILTER or CONFLUENCE_SPACES_FILTER when the operator credentials have broader access. The advisory traces the vulnerable input and processing flow through jira_search, confluence_search, get_board_issues, get_agile_boards, JIRA_PROJECTS_FILTER, and CONFLUENCE_SPACES_FILTER, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

CVSS v3
8.3
EG Score
8.3(low)
EG Risk
42(Track)
EG Risk 42/100SSVC: 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
Severity83% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

Published

September 22, 2026

Last Modified

September 22, 2026

Advisory Details (4)

Auto-updated Sep 22, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

v0.22.0

Patch available: sooperset/mcp-atlassian v0.22.0

https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
github_commit Patch Available

commit b041733473f9 (sooperset/mcp-atlassian)

Patch available: sooperset/mcp-atlassian v0.22.0 (contains commit b041733473f9)

https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
github_pr Patch Available

Security hardening across attachment, transport, SSRF, authorization, filter, and OAuth layers

Patch available: sooperset/mcp-atlassian v0.22.0 (PR #1448 merged 2026-07-10)

https://github.com/sooperset/mcp-atlassian/pull/1448
github Patch Available🟡 PoC Available

Three sub-bugs in JIRA_PROJECTS_FILTER / CONFLUENCE_SPACES_FILTER allow forbidden-project content exfiltration (one LIVE-proven on Atlassian Cloud) · Advisory · sooperset/mcp-atlassian · GitHub

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-w66g-j6c4-hcfc

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 3× in last 7d / 3× 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. 2026-09-22 18:30 UTCEG score recompute
  2. 2026-09-22 17:58 UTCEG score recompute
  3. 2026-09-22 17:58 UTCMITRE cvelistV5first tracked

Frequently asked(4)

What is CVE-2026-77251?
CVE-2026-77251 is a high vulnerability published on September 22, 2026. MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, Jira search accepts a forbidden project clause because it checks only for the presence of project syntax, Confluence search uses an incomplete case-sensitive space check, and Jira…
When was CVE-2026-77251 disclosed?
CVE-2026-77251 was first published in the National Vulnerability Database on September 22, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-77251?
CVE-2026-77251 has a CVSS v3 base score of 8.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-77251?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77251, 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

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