# CVE-2026-77167: Abusing the federated share endpoint, an attacker can write arbitrary rows into the oc_share_external database table.


- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026

## What is CVE-2026-77167?

CVE-2026-77167 is a high-severity vulnerability in Nextcloud server, published on 27 Oct 2026. 

### Official description

Abusing the federated share endpoint, an attacker can write arbitrary rows into the oc_share_external database table. These rows persist indefinitely — there is no automatic cleanup mechanism. Three distinct denial-of-service conditions follow from this write primitive, all triggered from the same unauthenticated source and all self-renewing on a 24-hour cycle for as long as the injected rows remain in the database.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-77167?


## How do I fix CVE-2026-77167?

No fix has been published for CVE-2026-77167 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-77167 being exploited?

There is no known exploitation of CVE-2026-77167 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77167 and fix it if it is affected.

What it is: CVE-2026-77167 is a high-severity vulnerability in Nextcloud server, published on 27 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-77167 in the wild and no public exploit code.

Affected product: Nextcloud server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-77167/ (Markdown: https://insights.sbomify.com/CVE-2026-77167/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77167
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77167
- OSV: https://osv.dev/vulnerability/CVE-2026-77167

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-77167/
Summaries are generated and may contain mistakes; the official description above is the record.