CVE-2026-55435: Anthropic Python — MEDIUM

### Summary AI Bridge proxy endpoints authenticate via `Server.IsAuthorized` in `coderd/aibridgedserver`, which validates key format, expiry, secret and deleted or system users but does not check whether the account is suspended. Because suspension does not revoke existing API keys, a suspended...

Full CISO analysis pending enrichment.

What systems are affected?

Package	Ecosystem	Vulnerable Range	Patched
Anthropic Python	go	>= 2.34.0, < 2.34.2	`2.34.2`
3.7K 5.4K dependents Pushed 4d ago 95% patched ~3d to patch Full package profile →

Do you use Anthropic Python? You're affected.

How severe is it?

CVSS 3.1

5.4 / 10

EPSS

N/A

Exploitation Status

No known exploitation

Sophistication

N/A

What is the attack surface?

AV Network

AC Low

PR Low

UI None

S Unchanged

C Low

I Low

A None

What should I do?

Patch available

Update Anthropic Python to version 2.34.2

Which compliance frameworks are affected?

Compliance analysis pending. Sign in for full compliance mapping when available.

Frequently Asked Questions

What is CVE-2026-55435?

### Summary AI Bridge proxy endpoints authenticate via `Server.IsAuthorized` in `coderd/aibridgedserver`, which validates key format, expiry, secret and deleted or system users but does not check whether the account is suspended. Because suspension does not revoke existing API keys, a suspended user's unexpired token keeps working. > **Note:** Practical impact is limited to already-issued API keys of suspended users until those keys are deleted. ### Impact A suspended user with a previously issued long-lived token could continue calling AI Bridge LLM proxy endpoints, consuming paid provider resources billed to the deployment and, if injected MCP tools are enabled, invoking those tools. Access persists until the token expires, which may be months after suspension. ### Patches The fix makes AI Bridge authorization reject non-active users like the standard API key middleware. AI Bridge was introduced in v2.30.0. The v2.29 ESR line is 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) | | 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) | ### Workarounds On suspension, delete the user's API keys via `DELETE /api/v2/users/{user}/keys`. ### Resources - Fix: #26173 ### Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22446) for independently disclosing this issue!

Is CVE-2026-55435 actively exploited?

No confirmed active exploitation of CVE-2026-55435 has been reported, but organizations should still patch proactively.

How to fix CVE-2026-55435?

Update to patched version: Anthropic Python 2.34.2.

What is the CVSS score for CVE-2026-55435?

CVE-2026-55435 has a CVSS v3.1 base score of 5.4 (MEDIUM).

What are the technical details?

Original Advisory

### Summary AI Bridge proxy endpoints authenticate via `Server.IsAuthorized` in `coderd/aibridgedserver`, which validates key format, expiry, secret and deleted or system users but does not check whether the account is suspended. Because suspension does not revoke existing API keys, a suspended user's unexpired token keeps working. > **Note:** Practical impact is limited to already-issued API keys of suspended users until those keys are deleted. ### Impact A suspended user with a previously issued long-lived token could continue calling AI Bridge LLM proxy endpoints, consuming paid provider resources billed to the deployment and, if injected MCP tools are enabled, invoking those tools. Access persists until the token expires, which may be months after suspension. ### Patches The fix makes AI Bridge authorization reject non-active users like the standard API key middleware. AI Bridge was introduced in v2.30.0. The v2.29 ESR line is 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) | | 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) | ### Workarounds On suspension, delete the user's API keys via `DELETE /api/v2/users/{user}/keys`. ### Resources - Fix: #26173 ### Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22446) for independently disclosing this issue!

Weaknesses (CWE)

CWE-863 Incorrect Authorization Primary

CWE-863 — Incorrect Authorization: The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

[Architecture and Design] Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
[Architecture and Design] Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].

Source: MITRE CWE corpus.