# CVE-2026-108103: Open5GS heap out-of-bounds read in PFCP parsing

Source: https://junglewise.ai/threats/cve-2026-108103-open5gs-through-2-8-0-contains-a-heap-out-of-bounds-read  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-09. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-108103 · Severity: medium · CVSS 5.3 · Published 2026-10-09

Open5GS is an open-source implementation of 5G core network functions. A heap out-of-bounds read vulnerability in the PFCP message parser allows remote attackers to crash the User Plane Function (UPF) component, potentially causing network service disruption. An attacker can send specially crafted PFCP packets over the network without authentication to trigger this vulnerability.

Technologies: [Open5GS](https://junglewise.ai/threats/technologies/open5gs). Vendors: [Open5GS](https://junglewise.ai/threats/vendors/open5gs).

## Quick answers

**Is CVE-2026-108103 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-108103 being exploited in the wild.

**How severe is CVE-2026-108103?** Medium severity, with a CVSS score of 5.3, published 9 October 2026.

**Which products and versions are affected?** Open5GS through 2.8.0.

**Is there a fix for CVE-2026-108103?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-108103 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-108103?** Check whether you run Open5GS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a heap out-of-bounds read in ogs_pfcp_parse_dropped_dl_traffic_threshold() that occurs when parsing short PFCP Information Elements (IEs). An unauthenticated remote attacker can send PFCP Session Establishment or Modification Requests with DLPA (Downlink Packet Access) and DLBY (Downlink Bytes) flags set to UDP port 8805, causing the parser to read past IE buffer boundaries. This typically results in denial of service via UPF crash.

## Affected products

- Open5GS Open5GS through 2.8.0

## Timeline

- 2026-10-09: disclosed

## References

- [https://github.com/open5gs/open5gs](https://github.com/open5gs/open5gs)
- [https://github.com/open5gs/open5gs/blob/v2.8.0/lib/pfcp/types.c](https://github.com/open5gs/open5gs/blob/v2.8.0/lib/pfcp/types.c)

## Related threats

- [Open5GS HTTP/2 SBI server memory exhaustion](https://junglewise.ai/threats/cve-2026-106806-a-memory-exhaustion-issue-exists-in-open5gs-v2-8-0-in-the-http-2)
- [open5GS PFCP transaction handling denial of service](https://junglewise.ai/threats/cve-2026-106807-a-denial-of-service-vulnerability-exists-in-open5gs-v2-8-0-in)
- [Open5GS heap out-of-bounds write in multipart parsing](https://junglewise.ai/threats/cve-2026-116543-open5gs-1-3-0-through-2-8-0-contains-a-heap-out-of-bounds-write)
- [Open5GS assertion failure in SGSN context request handling](https://junglewise.ai/threats/cve-2026-108105-open5gs-through-2-8-0-contains-a-reachable-assertion)
- [Open5GS heap out-of-bounds read in PFCP parsing](https://junglewise.ai/threats/cve-2026-108102-open5gs-through-2-8-0-contains-a-heap-out-of-bounds-read)