# CVE-2026-1521: Open5GS SGWC s5c-handler.c denial of service

> Remote attackers can cause a denial of service in Open5GS SGWC by manipulating bearer resource failure indications, requiring a patch to mitigate.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Jan 2026
- **Updated:** 23 Feb 2026
- **Also known as:** GHSA-8gqc-w5g5-j344

## What is CVE-2026-1521?

CVE-2026-1521 is a medium-severity denial of service vulnerability in Open5gs Open5gs, published on 28 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A security flaw has been discovered in Open5GS up to 2.7.6. This affects the function sgwc_s5c_handle_bearer_resource_failure_indication of the file src/sgwc/s5c-handler.c of the component SGWC. Performing a manipulation results in denial of service. The attack can be initiated remotely. The exploit has been released to the public and may be used for attacks. The patch is named 69b53add90a9479d7960b822fc60601d659c328b. It is recommended to apply a patch to fix this issue.

Weakness: CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2026-1521?

It affects 1 product.


Products: Open5gs Open5gs.

## How do I fix CVE-2026-1521?

No fix has been published for CVE-2026-1521 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-1521 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-1521 exists.

## Other vulnerabilities in Open5gs Open5gs

- [CVE-2024-40130](https://insights.sbomify.com/CVE-2024-40130/): Memory corruption in n/a (critical 9.8)
- [CVE-2021-28122](https://insights.sbomify.com/CVE-2021-28122/): Missing authorization in n/a (critical 9.8)
- [CVE-2021-25863](https://insights.sbomify.com/CVE-2021-25863/): Hardcoded credentials in n/a (high 8.8)
- [CVE-2025-41067](https://insights.sbomify.com/CVE-2025-41067/): Reachable Assertion vulnerability in Open5GS (high 8.7)
- [CVE-2025-41068](https://insights.sbomify.com/CVE-2025-41068/): Reachable Assertion vulnerability in Open5GS (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-1521 and fix it if it is affected.

What it is: CVE-2026-1521 is a medium-severity denial of service vulnerability in Open5gs Open5gs, published on 28 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-1521 exists.

Affected product: Open5gs Open5gs. 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-2026-1521/ (Markdown: https://insights.sbomify.com/CVE-2026-1521/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-1521
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-1521
- OSV: https://osv.dev/vulnerability/CVE-2026-1521

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-1521/
Summaries are generated and may contain mistakes; the official description above is the record.