How severe is CVE-2026-55435?

CVE-2026-55435 has a CVSS score of 5.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-55435?

CVE-2026-55435 affects the following packages: github.com/coder/coder/v2 (Go), github.com/coder/coder/v2 (Go), github.com/coder/coder/v2 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-55435?

Update github.com/coder/coder/v2 to 2.34.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55435 is resolved across your whole dependency graph.

How do I detect CVE-2026-55435 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/coder/coder/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-55435 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-55435 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55435 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 CVE-2026-55435?

CVE-2026-55435 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 22th 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 CVE-2026-55435?

CVE-2026-55435 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-55435 published, and has it been updated?

CVE-2026-55435 was published on July 7, 2026 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-55435 — v2

MEDIUMFix: coder/coder@0d2c9f9

CVE-2026-55435 is a medium-severity (CVSS 5.4) CWE-863 vulnerability in github.com/coder/coder/v2. A fix is available for github.com/coder/coder/v2 — see the affected versions and patch details below.

Suspended Coder users retain access to AI Bridge LLM proxy endpoints

Also known asGHSA-wqxv-w64v-5wh6GO-2026-5925

Published

Jul 7, 2026

Updated

Aug 12, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55435.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-55435 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 382,205 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

3 pkgs affected

🐹github.com/coder/coder/v2🐹github.com/coder/coder/v2🐹github.com/coder/coder/v2

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

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
2.33	v2.33.8
2.32	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!

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/coder/coder/v2`	≥ 2.34.0&&< 2.34.2	2.34.2`go get github.com/coder/coder/v2@v2.34.2`
🐹Go	`github.com/coder/coder/v2`	≥ 2.33.0&&< 2.33.8	2.33.8`go get github.com/coder/coder/v2@v2.33.8`
🐹Go	`github.com/coder/coder/v2`	≥ 2.30.0&&< 2.32.7	2.32.7`go get github.com/coder/coder/v2@v2.32.7`

Affected Products

1 product · 3 configurations

Application

codercoder

≥ 2.34.0 && < 2.34.2

range

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/coder/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/coder/coder/v2 to 2.34.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55435 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### 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 provide