CVE-2026-77248

HIGHPre-NVD 8.68.6—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 66% of all CVEs by exploit prediction. 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: epss, secondary
Trending — 3 sources updated this weekElevated
8.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.6Exploit: Elevated riskExposed: 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, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while upload_attachment accepts an unrestricted file_path. An unauthenticated network caller can read files available to the MCP process, upload them to an attacker-selected Jira issue or Confluence page, and retrieve the contents. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, upload_attachment, file_path, and _get_fetcher, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

CVSS v3
8.6
EG Score
8.6(medium)
EG Risk
70(Attend)
EG Risk 70/100SSVC: Attend

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
Severity86% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
34%
KEV
Not listed

Published

September 22, 2026

Last Modified

September 24, 2026

Advisory Details (4)

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

Unauthenticated arbitrary local file read via upload_attachment file_path, chained with missing auth on streamable-http transport · Advisory · sooperset/mcp-atlassian · GitHub

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-cc5h-2pwp-pvcc

Vendor Advisories for CVE-2026-77248(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
mcp-atlassian0.1.1 ... 0.9.0 (79 versions)0.22.0—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 8× 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. 2026-09-24 16:38 UTCEG score recompute
  2. 2026-09-24 15:32 UTCEG score recompute
  3. 2026-09-24 14:04 UTCEPSS rescore
  4. 2026-09-23 18:37 UTCEG score recompute
  5. 2026-09-23 17:54 UTCEPSS rescore
  6. 2026-09-22 19:37 UTCEG score recompute
  7. 2026-09-22 18:53 UTCEG score recompute
  8. 2026-09-22 18:53 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-77248?
CVE-2026-77248 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, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while uploadattachment accepts an unrestricted filepath. An…
When was CVE-2026-77248 disclosed?
CVE-2026-77248 was first published in the National Vulnerability Database on September 22, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77248 actively exploited?
CVE-2026-77248 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 66.5% of all scored CVEs.
What is the CVSS score of CVE-2026-77248?
CVE-2026-77248 has a CVSS v3 base score of 8.6 (NVD).
How do I remediate CVE-2026-77248?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-77248, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-77248

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