CVE-2025-59956: AgentAPI is an HTTP API for Claude Code, Goose, Aider, Gemini, Amp, and Codex

Q: How do I fix CVE-2025-59956?

agentapi: upgrade to 0.4.0. Exact commands for each OS are on this page.

Q: Is CVE-2025-59956 being exploited?

CVE-2025-59956 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-59956 affect?

CVE-2025-59956 affects agentapi. Severity is medium (CVSS 6.5). AgentAPI is an HTTP API for Claude Code, Goose, Aider, Gemini, Amp, and Codex. Versions 0.3.3 and below are susceptible to a client-side DNS rebinding attack when hosted over plain HTTP on localhost. An attacker can gain access to the /mess

Q: How urgent is CVE-2025-59956?

Priority 37/100. Public exploit reference

Routine

MEDIUM 6.5UPGRADE

CVE-2025-59956 is a medium-severity flaw (CVSS 6.5) affecting agentapi. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

AgentAPI is an HTTP API for Claude Code, Goose, Aider, Gemini, Amp, and Codex. Versions 0.3.3 and below are susceptible to a client-side DNS rebinding attack when hosted over plain HTTP on localhost. An attacker can gain access to the /messages endpoint served by the Agent API. This allows for the unauthorized exfiltration of sensitive user data, specifically local message history, which can include secret keys, file system contents, and intellec

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 63%)
CISA exploited list	No
Weakness	CWE-350, CWE-290
Published	2025-09-30
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: coder

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-09-30 11:37 UTCPublished CVE record published
2026-06-17 09:46 UTCUpdated Record last modified

coder agentapi UPGRADE

Affected: < 0.4.0

Fixed in: 0.4.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy agentapi || rpm -q agentapi || agentapi --version

2. UPGRADE to 0.4.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade agentapi

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade agentapi

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-59956?

agentapi: upgrade to 0.4.0. Exact commands for each OS are on this page.

Is CVE-2025-59956 being exploited?

CVE-2025-59956 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-59956 affect?

CVE-2025-59956 affects agentapi. Severity is medium (CVSS 6.5). AgentAPI is an HTTP API for Claude Code, Goose, Aider, Gemini, Amp, and Codex. Versions 0.3.3 and below are susceptible to a client-side DNS rebinding attack when hosted over plain HTTP on localhost. An attacker can gain access to the /mess

How urgent is CVE-2025-59956?

Priority 37/100. Public exploit reference

References

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