How severe is CVE-2026-23989?

CVE-2026-23989 has a CVSS score of 8.2/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-23989?

CVE-2026-23989 affects the following packages: github.com/opencloud-eu/reva/v2 (Go), github.com/opencloud-eu/reva/v2 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-23989?

Update github.com/opencloud-eu/reva/v2 to 2.40.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23989 is resolved across your whole dependency graph.

How do I detect CVE-2026-23989 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/opencloud-eu/reva/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-23989 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2026-23989 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-23989 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-23989?

CVE-2026-23989 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-23989?

CVE-2026-23989 is classified as CWE-863 (CWE-863). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-23989 published, and has it been updated?

CVE-2026-23989 was published on February 6, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

HIGH severity

CVE-2026-23989 — reva

HIGHFix: opencloud-eu/reva@95aa2bc

CVE-2026-23989 is a high-severity (CVSS 8.2) CWE-863 vulnerability in github.com/opencloud-eu/reva/v2. A fix is available for github.com/opencloud-eu/reva/v2 — see the affected versions and patch details below.

REVA Public Link Exploit

Also known asGHSA-9j2f-3rj3-wgpgGO-2026-4444

Published

Feb 6, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-23989.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk-0.00%

Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

🐹github.com/opencloud-eu/reva/v2🐹github.com/opencloud-eu/reva/v2

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

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.

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.

Patches

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

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]

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/opencloud-eu/reva/v2`	all versions	2.40.3`go get github.com/opencloud-eu/reva/v2@v2.40.3`
🐹Go	`github.com/opencloud-eu/reva/v2`	≥ 2.41.0&&< 2.42.3	2.42.3`go get github.com/opencloud-eu/reva/v2@v2.42.3`

Affected Products

1 product · 2 configurations

Application

opencloud revaheinlein

≥ 2.41.0 && < 2.42.3

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/opencloud-eu/reva/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/opencloud-eu/reva/v2 to 2.40.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23989 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### 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. ### 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 mal