frr: ospf6d fails to enforce all OSPFv3 packets use IPv6 link-local addresses
Summary
| CVE | CVE-2026-119776 |
|---|---|
| State | PUBLISHED |
| Assigner | NetDEF |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-11-04 15:17:41 UTC |
| Updated | 2026-11-04 17:17:35 UTC |
| 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. 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. |
Risk And Classification
Primary CVSS: v4.0 6.1 MEDIUM from 57a55968-44ac-464c-a794-6ba3baad09c4
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:X/U:X
Problem Types: CWE-304 | CWE-304 CWE-304 Missing critical step in authentication: protocol interactions should be limited to IPv6 link-local scope
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 57a55968-44ac-464c-a794-6ba3baad09c4 | Secondary | 6.1 | MEDIUM | 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/E:X/C... |
| 4.0 | CNA | CVSS | 6.1 | MEDIUM | 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 |
CVSS v4.0 Breakdown
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/FRRouting/frr/pull/23935 | 57a55968-44ac-464c-a794-6ba3baad09c4 | github.com | |
| github.com/FRRouting/frr/pull/24183/changes/eaccfcdb35bce8d94621b0663341... | 57a55968-44ac-464c-a794-6ba3baad09c4 | github.com | |
| github.com/FRRouting/frr/pull/24183 | 57a55968-44ac-464c-a794-6ba3baad09c4 | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Bing Shui <[email protected]> (not reported as security issue) (en)
CNA: Anthropic OSS-scanner (re-report, ANT-2026-N0E1INIV) (en)
Additional Advisory Data
Workarounds
CNA: 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.