# CVE-2026-73629: Serendipity before 2.6.0 SSRF via hex IPv4 and IPv6 addresses

> Authenticated users can bypass URL filters to access internal services and retrieve data via the uploads directory.

- **Severity:** High 8.4 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Aug 2026
- **Updated:** 14 Aug 2026
- **Also known as:** GHSA-2m48-gjj5-5x86, GHSA-fh9h-cxrw-2xj2

## What is CVE-2026-73629?

CVE-2026-73629 is a high-severity server-side request forgery vulnerability in s9y Serendipity, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Serendipity before 2.6.0 contains a server-side request forgery vulnerability in the serendipity_url_allowed() filter that fails to block hex-encoded IPv4 addresses, IPv6 literals, and link-local ranges. Authenticated users with adminImagesAdd permission can bypass the filter using alternate address formats to request internal services and retrieve response bodies through the public uploads directory.

Weakness: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-73629?


## How do I fix CVE-2026-73629?

No fix has been published for CVE-2026-73629 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-73629 being exploited?

There is no known exploitation of CVE-2026-73629 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-73629 and fix it if it is affected.

What it is: CVE-2026-73629 is a high-severity server-side request forgery vulnerability in s9y Serendipity, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-73629 in the wild and no public exploit code.

Affected product: s9y Serendipity. 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-2026-73629/ (Markdown: https://insights.sbomify.com/CVE-2026-73629/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-73629
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-73629
- OSV: https://osv.dev/vulnerability/CVE-2026-73629

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-73629/
Summaries are generated and may contain mistakes; the official description above is the record.