CVE-2026-97472: ipv6: addrconf: fix temp address generation after prefix deprecation

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-24 · updated 2026-10-03

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: addrconf: fix temp address generation after prefix deprecation When a router temporarily deprecates an IPv6 prefix (either by sending a Router Advertisement with Preferred Lifetime = 0 or by letting the lifetime expire) and later restores it, the kernel permanently loses its ability to generate temporary privacy addresses (RFC 8981) for that prefix. This happens because the address worker attempts to generate a replacement temporary address when the current one nears expiration. As the base prefix is deprecated already, the generation fails after marking the temporary address as already having spawned a replacement (ifp->regen_count++). When the router eventually restores the prefix, the temporary address becomes active again. However, once it naturally expires, the address worker sees this temporary address already tried to generate one and skips the regeneration. Fix the issue by resetting the regen_count check of the latest temp address generated for the prefix updated by the incoming RA.

Affected products

Linux kernel: 3.2 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

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