The vulnerability CVE-2026-25657 affects Ericsson Packet Core Gateway (PCG) versions before 1.30. It is classified as CWE-228, indicating improper handling of syntactically invalid structures. An attacker can exploit this by continuously sending specially crafted messages, leading to service degradation. The system experiences crashes during the attack but recovers automatically when the attack ceases. The CVSS 4.0 base score is 7.1, reflecting a high severity with attack vector being adjacent network, low attack complexity, no privileges or user interaction required, and high impact on availability. No patch or official remediation level has been published by Ericsson yet.

The vulnerability causes service degradation and system crashes in the affected Ericsson PCG product while under attack. The impact affects availability but does not persist after the attack stops, as the system recovers automatically. There is no indication of confidentiality or integrity impact. No known exploits have been reported in the wild.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Since no official patch or remediation level has been published, monitor Ericsson's advisories for updates. Until a fix is available, consider limiting exposure of the affected PCG to untrusted adjacent networks to reduce attack surface.