coder: Improper Authentication
CVE-2026-55076 is a high-severity improper authentication vulnerability in coder, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected coder versions: >= 2.34.0, < 2.34.2; >= 2.33.0, < 2.33.8; >= 2.30.0, < 2.32.7, and others listed below. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.61% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of coder you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Coder | coder | >= 2.34.0, < 2.34.2; >= 2.33.0, < 2.33.8; >= 2.30.0, < 2.32.7; < 2.29.17 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (github.com).
Official description
Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, Coder's OIDC callback checked `email_verified` with a direct Go `bool` type assertion. When an IdP returned the claim as a non-boolean (for example the string `"false"`) or omitted it, the assertion failed open and the email was treated as verified. Combined with an unconditional email-based account fallback, this enabled account takeover. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 coerces `email_verified` across bool, string and numeric types (fail-closed) and blocks the email fallback when the matched user already has a different linked IdP subject. As a workaround, ensure the IdP returns `email_verified` as a native JSON boolean. The email-fallback linking issue has no configuration workaround; upgrading is required.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/coder/coder/pull/25712Issue Tracking
- github.com/coder/coder/pull/25713Issue Tracking
- github.com/coder/coder/releases/tag/v2.29.17Release Notes
- github.com/coder/coder/releases/tag/v2.32.7Release Notes
- github.com/coder/coder/releases/tag/v2.33.8Release Notes
- github.com/coder/coder/releases/tag/v2.34.2Release Notes
Other vulnerabilities in coder
- 7.7 High severity
- 7.7 High severity
- 8.3 High severity
- 7.4 High severity
- 8.7 High severity
- 8.2 High severity
Recent Improper Authentication vulnerabilities
- 7.4 High severity
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 8.1 High severity
- 9.8 Critical severity
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