V2: Coder vulnerable to denial of service via unbounded request body in AI Bridge provider endpoints (CVE-2026-55434)
### Summary AI Bridge provider handlers read request bodies with `io.ReadAll` without a maximum size so an authenticated user with AI Bridge access could send an arbitrarily large body and exhaust memory. > **Note:** Exploitation requires authenticated access to the AI Bridge endpoints and the impact is limited to availability (denial of service). ### Impact An authenticated member-level user could POST a very large or chunked body to an AI Bridge provider endpoint such as `/api/v2/aibridge/anthropic/v1/messages`, growing heap memory until the operating system terminates the process. Because AI Bridge runs in-process with `coderd`, this crashes the entire control plane, including the API, workspace coordinator and DERP relay. It requires an authenticated user and the AI Bridge feature enabled. ### Patches The fix applies `http.MaxBytesReader` or an equivalent cap before reading provider and session request bodies. The affected AI Bridge provider endpoints exist only on the v2.33 and v2.34 lines. Earlier release lines are not affected. The fix is available in the following releases: | Release line | Patched version | |---|---| | 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) | | 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) | ### Workarounds None. ### Resources - Fix: #26164 ### Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22443) for independently disclosing this issue!
AI Analysis
Technical Summary
The AI Bridge provider handlers in github.com/coder/coder/v2 read request bodies using io.ReadAll without imposing a maximum size limit. This allows an authenticated user with AI Bridge access to send very large or chunked request bodies to endpoints such as /api/v2/aibridge/anthropic/v1/messages, leading to heap memory exhaustion. Since AI Bridge runs in-process with the coderd service, this results in the termination of the entire control plane process, including API, workspace coordinator, and DERP relay components. The vulnerability affects only versions in the 2.33 and 2.34 release lines prior to v2.33.8 and v2.34.2. The fix involves applying http.MaxBytesReader or an equivalent limit to cap request body size before reading.
Potential Impact
An authenticated user with AI Bridge access can cause a denial of service by sending an unbounded large request body, exhausting heap memory and crashing the coderd process. This disrupts the entire control plane, impacting availability of the API, workspace coordinator, and DERP relay. There is no impact on confidentiality or integrity. Exploitation requires authenticated access and the AI Bridge feature enabled.
Mitigation Recommendations
A fix is available in github.com/coder/coder/v2 versions v2.33.8 and later on the 2.33 release line, and v2.34.2 and later on the 2.34 release line. Users should upgrade to these versions to mitigate the vulnerability. No workarounds are available. Since this is not a cloud service, users must apply the patch themselves.
V2: Coder vulnerable to denial of service via unbounded request body in AI Bridge provider endpoints (CVE-2026-55434)
Description
### Summary AI Bridge provider handlers read request bodies with `io.ReadAll` without a maximum size so an authenticated user with AI Bridge access could send an arbitrarily large body and exhaust memory. > **Note:** Exploitation requires authenticated access to the AI Bridge endpoints and the impact is limited to availability (denial of service). ### Impact An authenticated member-level user could POST a very large or chunked body to an AI Bridge provider endpoint such as `/api/v2/aibridge/anthropic/v1/messages`, growing heap memory until the operating system terminates the process. Because AI Bridge runs in-process with `coderd`, this crashes the entire control plane, including the API, workspace coordinator and DERP relay. It requires an authenticated user and the AI Bridge feature enabled. ### Patches The fix applies `http.MaxBytesReader` or an equivalent cap before reading provider and session request bodies. The affected AI Bridge provider endpoints exist only on the v2.33 and v2.34 lines. Earlier release lines are not affected. The fix is available in the following releases: | Release line | Patched version | |---|---| | 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) | | 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) | ### Workarounds None. ### Resources - Fix: #26164 ### Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22443) for independently disclosing this issue!
CVSS v3.1
Score 6.5medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The AI Bridge provider handlers in github.com/coder/coder/v2 read request bodies using io.ReadAll without imposing a maximum size limit. This allows an authenticated user with AI Bridge access to send very large or chunked request bodies to endpoints such as /api/v2/aibridge/anthropic/v1/messages, leading to heap memory exhaustion. Since AI Bridge runs in-process with the coderd service, this results in the termination of the entire control plane process, including API, workspace coordinator, and DERP relay components. The vulnerability affects only versions in the 2.33 and 2.34 release lines prior to v2.33.8 and v2.34.2. The fix involves applying http.MaxBytesReader or an equivalent limit to cap request body size before reading.
Potential Impact
An authenticated user with AI Bridge access can cause a denial of service by sending an unbounded large request body, exhausting heap memory and crashing the coderd process. This disrupts the entire control plane, impacting availability of the API, workspace coordinator, and DERP relay. There is no impact on confidentiality or integrity. Exploitation requires authenticated access and the AI Bridge feature enabled.
Mitigation Recommendations
A fix is available in github.com/coder/coder/v2 versions v2.33.8 and later on the 2.33 release line, and v2.34.2 and later on the 2.34 release line. Users should upgrade to these versions to mitigate the vulnerability. No workarounds are available. Since this is not a cloud service, users must apply the patch themselves.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-f5vp-w269-392g
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-55434"]
- Ecosystems
- ["Go"]
- Database Specific Severity
- MODERATE
- Cvss Version
- 3.1
Threat ID: 6a4c340227e9c797195f5e6a
Added to database: 07/06/2026, 23:02:26 UTC
Last enriched: 07/06/2026, 23:11:55 UTC
Last updated: 07/31/2026, 19:50:59 UTC
Views: 29
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