CVE-2025-59956Public exploitNetwork attack vector

Message history disclosure via missing origin validation

Published Sep 29, 2025 · Updated Sep 30, 2025

Origin validation error in Coder AgentAPI before 0.4.0 allows remote attackers to read local message history through DNS rebinding. The localhost HTTP server accepts browser requests to /messages without validating the Host or Origin headers, letting a rebound attacker-controlled domain retrieve its JSON response. Exploitation requires plain HTTP, a running local service, and a visit to malicious content; disclosure is limited to conversation data exposed by /messages.

CVSS severity6.5
Medium
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in Coder AgentAPI before 0.4.0 allows remote attackers to read local message history through DNS rebinding. The localhost HTTP server accepts browser requests to /messages without validating the Host or Origin headers, letting a rebound attacker-controlled domain retrieve its JSON response. Exploitation requires plain HTTP, a running local service, and a visit to malicious content; disclosure is limited to conversation data exposed by /messages.

The record

CVE
CVE-2025-59956
Published
Sep 29, 2025
Updated
Sep 30, 2025
Vendor
Coder
Product
AgentAPI
Classifications
CWE-346, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Coder · AgentAPIversion=< 0.4.0

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-346Origin Validation Error
T1189Drive-by Compromise

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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