CVE-2026-77255

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.45% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 39.5% of scored records. A rank, not a probability.

NVD base score

8.6 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

NVD analysis status

Analyzed. NVD last modified this record on 2026-09-29.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-09-22 18:29Z1 MO AGO

Last updated

2026-09-26 00:00Z1 MO AGO

Reserved

2026-08-20

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

High (CVSS 8.6)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Weaknesses

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')Base
• CWE-441Unintended Proxy or Intermediary ('Confused Deputy')Class

Data version

5.2

Document digest

01516220882b65e950ae3ec65a908f68f908a1c2c4961a88bc2e852bfa4174a1

• github.comhttps://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwcx_refsource_CONFIRM
• github.comhttps://github.com/sooperset/mcp-atlassian/pull/1448x_refsource_MISC
• github.comhttps://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460x_refsource_MISC
• github.comhttps://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0x_refsource_MISC