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.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Thu, 24 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | ipv6: addrconf: fix temp address generation after prefix deprecation | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-24T16:04:14.951Z
Reserved: 2026-09-24T16:01:01.148Z
Link: CVE-2026-97472
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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No weakness.