---
title: "CVE-2026-63398: Coop - Broken Access Control"
description: "Coop prior to 1.0.2 contains a broken access control vulnerability caused by SAML strategy's verify callback resolving users by email without organization binding, letting attackers with control of a SAML IdP signing key perform cross-tenant account takeover, exploit requires matching signing certificate in target organization."
url: https://panop.io/threat-heartbeat/CVE-2026-63398/
---

# CVE-2026-63398 Coop - Broken Access Control

Coop prior to 1.0.2 contains a broken access control vulnerability caused by SAML strategy's verify callback resolving users by email without organization binding, letting attackers with control of a SAML IdP signing key perform cross-tenant account takeover, exploit requires matching signing certificate in target organization.

CVSS base score 7.4 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.18% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-63398)

## Details

Type

Broken Access Control

Impact

Broken Access Control

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Published

30 October 2026

Updated

1 November 2026

Weakness

[CWE-287](https://cwe.mitre.org/data/definitions/287.html)

## Vendor fix

Update to version 1.0.2 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-63398](https://nvd.nist.gov/vuln/detail/CVE-2026-63398)
- [https://github.com/roostorg/coop/pull/783](https://github.com/roostorg/coop/pull/783)
- [https://github.com/roostorg/coop/releases/tag/1.0.2](https://github.com/roostorg/coop/releases/tag/1.0.2)
- [https://github.com/roostorg/coop/security/advisories/GHSA-2v93-383c-9fw2](https://github.com/roostorg/coop/security/advisories/GHSA-2v93-383c-9fw2)
- [https://github.com/roostorg/coop/commit/d1be81b6b33abc1162ee6b9952d4bd1ca761b071](https://github.com/roostorg/coop/commit/d1be81b6b33abc1162ee6b9952d4bd1ca761b071)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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