How severe is GHSA-w64r-2g3w-w8w4?

GHSA-w64r-2g3w-w8w4 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-w64r-2g3w-w8w4?

GHSA-w64r-2g3w-w8w4 affects the following packages: github.com/coder/agentapi (Go). Ecosystems affected: Go.

How do I fix GHSA-w64r-2g3w-w8w4?

Update github.com/coder/agentapi to 0.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w64r-2g3w-w8w4 is resolved across your whole dependency graph.

How do I detect GHSA-w64r-2g3w-w8w4 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/coder/agentapi. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-w64r-2g3w-w8w4 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-w64r-2g3w-w8w4?

O3 pinpoints whether GHSA-w64r-2g3w-w8w4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-w64r-2g3w-w8w4 actively exploited in the wild?

No public exploit code has been indexed for GHSA-w64r-2g3w-w8w4 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-w64r-2g3w-w8w4?

GHSA-w64r-2g3w-w8w4 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 31th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-w64r-2g3w-w8w4?

GHSA-w64r-2g3w-w8w4 is classified as CWE-350 (CWE-350), CWE-290 (CWE-290). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-w64r-2g3w-w8w4 published, and has it been updated?

GHSA-w64r-2g3w-w8w4 was published on September 29, 2025 and was last updated on October 23, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

GHSA-w64r-2g3w-w8w4

MEDIUM

Coder AgentAPI exposed user chat history via a DNS rebinding attack

Also known asCVE-2025-59956GO-2025-3991

Published

Sep 29, 2025

Updated

Oct 23, 2025

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk31th percentile+0.32%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐹github.com/coder/agentapi

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Summary

AgentAPI prior to version 0.4.0 was susceptible to a client-side DNS rebinding attack when hosted over plain HTTP on localhost.

Impact

An attacker could have gained access to the /messages endpoint served by the Agent API. This allowed for the unauthorized exfiltration of sensitive user data, specifically local message history, which could've included secret keys, file system contents, and intellectual property the user was working on locally.

Remediation

We've implemented an Origin and Host header validating middleware and set a secure by default configuration.

Please upgrade to version 0.4.0 or later.

Credits

We'd like to thank Evan Harris from mcpsec.dev for reporting this issue and following the coordinated disclosure policy.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/coder/agentapi`	all versions	0.4.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/coder/agentapi. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/coder/agentapi to 0.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w64r-2g3w-w8w4 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-w64r-2g3w-w8w4 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-w64r-2g3w-w8w4. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary AgentAPI prior to version [0.4.0](https://github.com/coder/agentapi/releases/tag/v0.4.0) was susceptible to a client-side DNS rebinding attack when hosted over plain HTTP on localhost. ### Impact An attacker could have gained access to the `/messages` endpoint served by the Agent API. This allowed for the unauthorized exfiltration of sensitive user data, specifically local message history, which could've included secret keys, file system contents, and intellectual property the user was working on locally. ### Remediation We've [implemented](https://github.com/coder/agentapi/pull/

O3 Security · Impact-Aware SCA

Is GHSA-w64r-2g3w-w8w4 in your dependencies?

O3 detects GHSA-w64r-2g3w-w8w4 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works