CVE-2026-91855 Details
Description
A security flaw has been discovered in Open5GS up to 2.7.7. Affected by this vulnerability is an unknown functionality of the file lib/pfcp/handler.c of the component PFCP Message Handler. Performing a manipulation results in denial of service. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks. The patch is named 028e1dbb5e3271035ccee906ef417a97fc523f71. Applying a patch is the recommended action to fix this issue. CVE-2025-29339 describes a different assertion failure vulnerability in Open5GS UPF.
A denial-of-service vulnerability has been identified in Open5GS versions through 2.7.7, specifically within the PFCP Message Handler component. The issue arises from improper validation of the Outer Header Creation field in PFCP Session Establishment messages, which can be exploited remotely. When the UPF receives malformed Outer Header Creation data, it can lead to a crash by causing an uninitialized address structure to be processed, triggering a fatal error and terminating the UPF process. This vulnerability disrupts active sessions and can be reproduced by sending a sequence of crafted PFCP messages.
Users can upgrade to Open5GS version 2.8.0 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 15, 2026CISA-ADP
Assessed Sep 15, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/open5gs/open5gs/ | [email protected] | ProductSource CodeVendor |
| https://github.com/open5gs/open5gs/commit/028e1dbb5e3271035ccee906ef417a97fc523f71 | [email protected] | Source CodeVendor |
| https://github.com/open5gs/open5gs/issues/4699 | [email protected] | ExploitIssue TrackingTechnical DescriptionVendor |
| https://vuldb.com/cve/CVE-2026-91855 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/submit/933834 | [email protected] | Issue TrackingPermission Required |
| https://vuldb.com/vuln/404086 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/vuln/404086/cti | [email protected] | Content Wall |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-404 | Improper Resource Shutdown or Release | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Open5GS | <= 2.7.7 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 15, 2026 | CVE Modified | CISA-ADP |
| Sep 15, 2026 | New CVE Received | [email protected] |