In all prior released versions of FRRouting, the OSPFv3 (for IPv6) implementation does not check that OSPFv3 packets have a link-local source address and either a link-local destination or one of the protocol multicast destination groups. This may enable malicious actors to establish OSPFv3 adjacencies from unexpectedly, distant IPv6 hosts. Proper usage of OSPFv3 authentication trailers (RFC 7166, as is best practice) prevents full exploitation of this issue, though may allow a malicious actor to waste CPU on authentication checks.


Note the linked PR #23935 is not sufficient to fix the issue as it only verifies the source address. It is the destination address that must be checked.


Required configuration: The OSPFv3 for IPv6 routing protocol must be running (ospf6d process) and in use (enabled globally with "router ospf6" and on specific interfaces with "ipv6 ospf6 area".)


Workaround: either:

* configure OSPFv3 authentication trailers ("ipv6 ospf6 authentication")
* or ensure through firewall configuration that only packets with link-local or multicast destination addresses are accepted on input for IPv6 protocol 89 (OSPF). Note that checking the source address is insufficient, as some routers may (unexpectedly) forward packets with global-scoped IPv6 destination addresses even if they have link-local source addresses.
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

Either: * configure OSPFv3 authentication trailers ("ipv6 ospf6 authentication") * or ensure through firewall configuration that only packets with link-local or multicast destination addresses are accepted on input for IPv6 protocol 89 (OSPF). Note that checking the source address is insufficient, as some routers may (unexpectedly) forward packets with global-scoped IPv6 destination addresses even if they have link-local source addresses.

History

Wed, 04 Nov 2026 17:00:00 +0000

Type Values Removed Values Added
Description In all prior released versions of FRRouting, the OSPFv3 (for IPv6) implementation does not check that OSPFv3 packets have a link-local source address and either a link-local destination or one of the protocol multicast destination groups. This may enable malicious actors to establish OSPFv3 adjacencies from unexpectedly, distant IPv6 hosts. Proper usage of OSPFv3 authentication trailers (RFC 7166, as is best practice) prevents full exploitation of this issue, though may allow a malicious actor to waste CPU on authentication checks. Note the linked PR #23935 is not sufficient to fix the issue as it only verifies the source address. It is the destination address that must be checked. In all prior released versions of FRRouting, the OSPFv3 (for IPv6) implementation does not check that OSPFv3 packets have a link-local source address and either a link-local destination or one of the protocol multicast destination groups. This may enable malicious actors to establish OSPFv3 adjacencies from unexpectedly, distant IPv6 hosts. Proper usage of OSPFv3 authentication trailers (RFC 7166, as is best practice) prevents full exploitation of this issue, though may allow a malicious actor to waste CPU on authentication checks. Note the linked PR #23935 is not sufficient to fix the issue as it only verifies the source address. It is the destination address that must be checked. Required configuration: The OSPFv3 for IPv6 routing protocol must be running (ospf6d process) and in use (enabled globally with "router ospf6" and on specific interfaces with "ipv6 ospf6 area".) Workaround: either: * configure OSPFv3 authentication trailers ("ipv6 ospf6 authentication") * or ensure through firewall configuration that only packets with link-local or multicast destination addresses are accepted on input for IPv6 protocol 89 (OSPF). Note that checking the source address is insufficient, as some routers may (unexpectedly) forward packets with global-scoped IPv6 destination addresses even if they have link-local source addresses.
Title FRRouting OSPFv3 Address Validation Vulnerability frr: ospf6d fails to enforce all OSPFv3 packets use IPv6 link-local addresses

Wed, 04 Nov 2026 16:15:00 +0000

Type Values Removed Values Added
Title FRRouting OSPFv3 Address Validation Vulnerability

Wed, 04 Nov 2026 14:30:00 +0000

Type Values Removed Values Added
Description In all prior released versions of FRRouting, the OSPFv3 (for IPv6) implementation does not check that OSPFv3 packets have a link-local source address and either a link-local destination or one of the protocol multicast destination groups. This may enable malicious actors to establish OSPFv3 adjacencies from unexpectedly, distant IPv6 hosts. Proper usage of OSPFv3 authentication trailers (RFC 7166, as is best practice) prevents full exploitation of this issue, though may allow a malicious actor to waste CPU on authentication checks. Note the linked PR #23935 is not sufficient to fix the issue as it only verifies the source address. It is the destination address that must be checked.
First Time appeared Frrouting
Frrouting frrouting
Weaknesses CWE-304
CPEs cpe:2.3:a:frrouting:frrouting:*:*:*:*:*:*:*:*
Vendors & Products Frrouting
Frrouting frrouting
References
Metrics cvssV4_0

{'score': 6.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N/AU:Y'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: NetDEF

Published:

Updated: 2026-11-04T16:53:47.660Z

Reserved: 2026-10-30T16:14:17.897Z

Link: CVE-2026-119776

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-04T15:17:41.400

Modified: 2026-11-04T17:17:35.090

Link: CVE-2026-119776

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-11-04T16:00:17Z

Weaknesses