Summary
Details
Public link shares in OpenCloud are bound to a specific scope (usually a file or directory). Anonymous users accessing resources via this public link share are only allowed to access the share resource itself and, in case of a directory or space root, all child resources of it.
Due to a bug in the GRPC authorization middleware of the "Reva" component of OpenCloud a malicious user is able to bypass the scope verification. By exploiting this via the the "archiver" service this can be leveraged to create an archive (zip or tar-file) containing all resources that this creator of the public link has access to.
It is not possible to bypass the public link scope via "normal" WebDAV requests so it is not possible to exploit this vulnerability via WebDAV.
Workarounds
There is no workaround because one cannot run Reva standalone from this project. Please check the OpenCloud Advisory how to mitigate the problem in an OpenCloud deployment via configuration.
For more information
If there are any questions or comments about this advisory:
- Security Support: [email protected]
- Technical Support: [email protected]
Impact
A security issue was discovered in Reva based products that enables a malicious user to bypass the scope validation of a public link, allowing it to access resources outside the scope of a public link.
Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.
CVE-2026-23989 has a CVSS score of 8.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.40.3, 2.42.3); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Update to OpenCloud Reva version >= 2.40.3 for the 2.40.x versions.
Update to OpenCloud Reva version >= 2.42.3 for the 2.41.x versions
Frequently Asked Questions
- What is CVE-2026-23989? CVE-2026-23989 is a high-severity path traversal vulnerability in github.com/opencloud-eu/reva/v2 (go), affecting versions <= 2.40.1. It is fixed in 2.40.3, 2.42.3. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
- How severe is CVE-2026-23989? CVE-2026-23989 has a CVSS score of 8.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/opencloud-eu/reva/v2 are affected by CVE-2026-23989? github.com/opencloud-eu/reva/v2 (go) versions <= 2.40.1 is affected.
- Is there a fix for CVE-2026-23989? Yes. CVE-2026-23989 is fixed in 2.40.3, 2.42.3. Upgrade to this version or later.
- Is CVE-2026-23989 exploitable, and should I be worried? Whether CVE-2026-23989 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-23989 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-23989?
- Upgrade
github.com/opencloud-eu/reva/v2to 2.40.3 or later - Upgrade
github.com/opencloud-eu/reva/v2to 2.42.3 or later
- Upgrade