How severe is CVE-2026-48529?

CVE-2026-48529 has a CVSS 3.x base score of 6.0, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-48529 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-48529?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-48529 published?

CVE-2026-48529 was published on 2026-06-26 and last updated on 2026-06-27.

CVE-2026-48529

CVE-2026-48529 is a medium-severity vulnerability with a CVSS 3.x base score of 6.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Medium (CVSS 3.x base score 6.0)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Published: 2026-06-26
Last modified: 2026-06-27

Description

GitHub MCP Server is GitHub's official MCP Server. From 0.22.0 until 1.1.2, when running in HTTP mode with --lockdown-mode enabled, the RepoAccessCache is implemented as a process-global singleton initialized with the first authenticated user's GraphQL client. All subsequent requests from different users share this singleton and their lockdown-related GraphQL queries are executed using the first user's credentials. The singleton is never updated to reflect later users' tokens. This vulnerability is fixed in 1.1.2.

Frequently asked questions

What is CVE-2026-48529?: GitHub MCP Server is GitHub's official MCP Server. From 0.22.0 until 1.1.2, when running in HTTP mode with --lockdown-mode enabled, the RepoAccessCache is implemented as a process-global singleton initialized with the first authenticated user's GraphQL client. All subsequent requests from different users share this singleton and their lockdown-related GraphQL queries are executed using the first user's credentials. The singleton is never updated to reflect later users' tokens. This vulnerability is fixed in 1.1.2.
How severe is CVE-2026-48529?: CVE-2026-48529 has a CVSS 3.x base score of 6.0, rated medium severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-48529 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-48529?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-48529 published?: CVE-2026-48529 was published on 2026-06-26 and last updated on 2026-06-27.

References

https://github.com/github/github-mcp-server/security/advisories/GHSA-pjp5-fpmr-3349

Other CWE-284 (Improper Access Control) vulnerabilities

CVE-2026-50746 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Access Control vulnerability found in UniFi…
CVE-2026-46978 — Critical (CVSS 10.0): Vulnerability in the Oracle Solaris product of Oracle Systems (component: Remote Administration Daemon). The…
CVE-2026-35308 — Critical (CVSS 10.0): Vulnerability in the Oracle Coherence product of Oracle Fusion Middleware (component: Centralized Third Party Jars).…
CVE-2026-35307 — Critical (CVSS 10.0): Vulnerability in the Oracle Coherence product of Oracle Fusion Middleware (component: Core). Supported versions that…
CVE-2026-46695 — Critical (CVSS 10.0): Boxlite is a sandbox service that allows users to create lightweight virtual machines (Boxes) and launch OCI containers…
CVE-2026-46840 — Critical (CVSS 10.0): Vulnerability in Oracle REST Data Services (component: Backend-as-a-Service). Supported versions that are affected are…

Browse all CWE-284 (Improper Access Control) vulnerabilities →