Bug 2466981 (CVE-2026-43088)

Summary: CVE-2026-43088 kernel: net: af_key: zero aligned sockaddr tail in PF_KEY exports
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's AF_KEY networking component. When handling PF_KEY export paths, the pfkey_sockaddr_fill() function does not fully initialize sockaddr_in6 structures, leaving 4 bytes of memory uninitialized. This can lead to the disclosure of potentially sensitive information from the kernel's memory.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-05-06 10:01:42 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net: af_key: zero aligned sockaddr tail in PF_KEY exports

PF_KEY export paths use `pfkey_sockaddr_size()` when reserving sockaddr
payload space, so IPv6 addresses occupy 32 bytes on the wire. However,
`pfkey_sockaddr_fill()` initializes only the first 28 bytes of
`struct sockaddr_in6`, leaving the final 4 aligned bytes uninitialized.

Not every PF_KEY message is affected. The state and policy dump builders
already zero the whole message buffer before filling the sockaddr
payloads. Keep the fix to the export paths that still append aligned
sockaddr payloads with plain `skb_put()`:

  - `SADB_ACQUIRE`
  - `SADB_X_NAT_T_NEW_MAPPING`
  - `SADB_X_MIGRATE`

Fix those paths by clearing only the aligned sockaddr tail after
`pfkey_sockaddr_fill()`.
Comment 1 Alexander B 2026-05-06 15:23:39 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050616-CVE-2026-43088-31b9@gregkh/T