Is CVE-2026-48529 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-48529 being exploited in the wild.

How severe is CVE-2026-48529?

Medium severity, with a CVSS score of 6, published 26 June 2026.

Which products and versions are affected?

Github-Mcp-Server >= 0.22.0, = 0.22.0, < 1.1.2, SEMVER:introduced=0.22.0,fixed=1.1.2.

Is there a fix for CVE-2026-48529?

Yes. github.com/github/github-mcp-server (Go): upgrade to 1.1.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-48529 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-48529?

Check whether you run Github-Mcp-Server or github.com/github/github-mcp-server (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-48529: GitHub MCP Server improper access control in lockdown mode

Q: Is there a fix for CVE-2026-48529?

Yes. github.com/github/github-mcp-server (Go): upgrade to 1.1.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-48529 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-48529?

Check whether you run Github-Mcp-Server or github.com/github/github-mcp-server (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-48529 · Severity: medium · CVSS 6 · Published 2026-06-26

The GitHub MCP Server, which facilitates communication between AI models and GitHub data, contains a flaw when running in multi-user HTTP mode. The system incorrectly reuses the security credentials of the very first person who logs in for all subsequent users. This can lead to incorrect security decisions, such as failing to sanitize malicious content or blocking legitimate users from accessing their own data if the first user's session expires.

Vendors: GitHub, Go.

Quick answers

Is CVE-2026-48529 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-48529 being exploited in the wild.
How severe is CVE-2026-48529?: Medium severity, with a CVSS score of 6, published 26 June 2026.
Which products and versions are affected?: Github-Mcp-Server >= 0.22.0, < 1.1.2; github.com/github/github-mcp-server (Go) >= 0.22.0, < 1.1.2, SEMVER:introduced=0.22.0,fixed=1.1.2.
Is there a fix for CVE-2026-48529?: Yes. github.com/github/github-mcp-server (Go): upgrade to 1.1.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-48529 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-48529?: Check whether you run Github-Mcp-Server or github.com/github/github-mcp-server (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

github.com/github/github-mcp-server (Go): upgrade to 1.1.2 or later
```
go get github.com/github/github-mcp-server@v1.1.2
```

Technical details

A vulnerability exists in the RepoAccessCache implementation of the GitHub MCP Server (versions 0.22.0 to 1.1.1). When running in HTTP mode with --lockdown-mode enabled, the RepoAccessCache is implemented as a process-global singleton that is initialized only once with the first authenticated user's GraphQL client. Subsequent requests from different users share this singleton, causing their lockdown-related GraphQL queries (which determine repository visibility and collaborator access) to execute using the first user's credentials. This can result in incorrect IsSafeContent decisions, potentially allowing unsanitized content from untrusted contributors to reach the AI model, or causing service denial if the initial user's token expires. The issue is fixed in version 1.1.2.

Affected products

GitHub github-mcp-server >= 0.22.0, < 1.1.2

Identifiers

CVE-2026-48529
GHSA-pjp5-fpmr-3349
GO-2026-5779

Timeline

2026-06-09: advisory: GitHub security advisory published
2026-06-26: disclosed: CVE-2026-48529 published to NVD
2026-06-26: patched: Vulnerability fixed in version 1.1.2

References

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

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