CVE-2026-119776
Description
A flaw was found in FRRouting. The Open Shortest Path First version 3 (OSPFv3) implementation does not validate that incoming network packets originate from and are destined for expected local network addresses. A remote attacker can exploit this flaw by sending specially crafted packets from a distant network to establish unauthorized routing adjacencies. Successful exploitation may allow the attacker to manipulate network routing or cause a Denial of Service (DoS) by exhausting system resources.
Mitigation
--- CME Mitigation Guidance (2026-11-04) ---
Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to independently evaluate and test these temporary mitigations within their own infrastructure.
The highest-value action is to enforce strict link-local and multicast address validation on incoming OSPFv3 protocol 89 packets in ospf6d: upgrade to the fixed Frr builds, which drop incoming OSPFv3 packets in ospf6_read_helper() when the destination is not link-local or an OSPF multicast group or when the source is not link-local, closing all 2 injection vectors (crafted OSPFv3 packets with global unicast destination addresses, crafted OSPFv3 packets with non-link-local source addresses). Until patched, this is a concern on Linux systems running FRRouting ospf6d processing IPv6 OSPFv3 traffic exposed to external networks, so Filter IPv6 protocol 89 traffic at network perimeters to allow only link-local or designated multicast destinations and enforce OSPFv3 authentication trailers (RFC 7166). These controls limit blast radius and contain exploitation, but they do not fix the underlying missing address validation defect — apply the upstream patch to fully remediate.
Highest-impact CME: CME-1315 Allowlist-Preferred Input Validation (Deny-by-Default Filtering) (high)
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.7 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | High | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | High | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:H
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context; Bypass Protection Mechanism
An attacker from an untrusted origin could successfully establish a communication channel. The attacker could then gain privileges and access unexpected functionality that was only intended for trusted sources.
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