CVE-2026-43088: net: af_key: zero aligned sockaddr tail in PF_KEY exports

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-06 · updated 2026-09-14

Description

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()`.

Affected products

Linux kernel: from 2.6.12.1 before 6.12.88; from 6.13 before 6.18.30; from 6.19 before 6.19.14; 2.6.12, 2.6.12-rc2, 2.6.12-rc3, 2.6.12-rc4, 2.6.12-rc5, 7.0-rc1 (+6) — fixed in 6.12.88, 6.18.30, 6.19.14

How to fix

Upgrade to a fixed version: Linux kernel 6.12.88, 6.18.30, 6.19.14. Check the vendor advisory for mitigations.

References

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