CVE-2026-46354: Coder: PKCS#7 signature bypass in Azure instance identity allows unauthenticated agent token theft

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-07 · updated 2026-07-08
Weakness: CWE-347

Description

Coder allows organizations to provision remote development environments via Terraform. In versions prior tp 2.24.5, 2.29.13, 2.30.8, 2.31.12, 2.32.2, and 2.33.3, `azureidentity.Validate()` verifies that the PKCS#7 signer certificate chains to a trusted Azure CA but never verifies the PKCS#7 signature itself. An attacker can embed a legitimate Azure certificate alongside arbitrary content e.g. `{"vmId":"<target>"}` and the forged `vmId` will be accepted returning the victim workspace agent's session token. No authentication is required. The attacker only needs to know a target VM's `vmId` which is a `UUIDv4`. That's a practical limitation which would typically require prior access to be exploited. Versions 2.24.5, 2.29.13, 2.30.8, 2.31.12, 2.32.2, and 2.33.3 patch the issue. As a workaround, reconfigure any Azure templates to use token authentication rather than `azure-instance-identity`.

Affected products

coder: before 2.24.5; from 2.29.0 before 2.29.13; from 2.30.0 before 2.30.8; from 2.31.0 before 2.31.12; from 2.32.0 before 2.32.2; from 2.33.0 before 2.33.3 — fixed in 2.24.5, 2.29.13, 2.30.8, 2.31.12, 2.32.2, 2.33.3

How to fix

Upgrade to a fixed version: coder 2.24.5, 2.29.13, 2.30.8, 2.31.12. Check the vendor advisory for mitigations.

References

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