GHSA-75VM-6W67-GWVP
Vulnerability from github – Published: 2026-07-06 20:50 – Updated: 2026-07-06 20:50Summary
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.
Impact
An attacker who registered a victim's email at a compatible IdP without verifying it could log in via OIDC and be matched to the victim's existing Coder account, receiving a session for that account. No prior authentication to Coder was required and the result was full account takeover.
Patches
The fix 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.
The fix was backported to all supported release lines:
| Release line | Patched version |
|---|---|
| 2.34 | v2.34.2 |
| 2.33 | v2.33.8 |
| 2.32 | v2.32.7 |
| 2.29 (ESR) | v2.29.17 |
Workarounds
Ensure the IdP returns email_verified as a native JSON boolean. The email-fallback linking issue has no configuration workaround; upgrading is required.
Resources
- Fix: #25712, #25713
Credits
Coder would like to thank Anthropic's Security Team (ANT-2026-22444) for independently disclosing this issue!
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/coder/coder/v2"
},
"ranges": [
{
"events": [
{
"introduced": "2.34.0"
},
{
"fixed": "2.34.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Go",
"name": "github.com/coder/coder/v2"
},
"ranges": [
{
"events": [
{
"introduced": "2.33.0"
},
{
"fixed": "2.33.8"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Go",
"name": "github.com/coder/coder/v2"
},
"ranges": [
{
"events": [
{
"introduced": "2.30.0"
},
{
"fixed": "2.32.7"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Go",
"name": "github.com/coder/coder/v2"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.29.17"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-55076"
],
"database_specific": {
"cwe_ids": [
"CWE-287",
"CWE-704"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-06T20:50:35Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Summary\n\nCoder\u0027s 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.\n\n### Impact\n\nAn attacker who registered a victim\u0027s email at a compatible IdP without verifying it could log in via OIDC and be matched to the victim\u0027s existing Coder account, receiving a session for that account. No prior authentication to Coder was required and the result was full account takeover.\n\n### Patches\n\nThe fix 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.\n\nThe fix was backported to all supported release lines:\n\n| Release line | Patched version |\n|---|---|\n| 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) |\n| 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) |\n| 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) |\n| 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) |\n\n### Workarounds\n\nEnsure the IdP returns `email_verified` as a native JSON boolean. The email-fallback linking issue has no configuration workaround; upgrading is required.\n\n### Resources\n\n- Fix: #25712, #25713\n\n### Credits\n\nCoder would like to thank Anthropic\u0027s Security Team (ANT-2026-22444) for independently disclosing this issue!",
"id": "GHSA-75vm-6w67-gwvp",
"modified": "2026-07-06T20:50:35Z",
"published": "2026-07-06T20:50:35Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/coder/coder/security/advisories/GHSA-75vm-6w67-gwvp"
},
{
"type": "PACKAGE",
"url": "https://github.com/coder/coder"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "Coder\u0027s OIDC email_verified type coercion bypass enables account takeover via unverified email linking"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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