CVE-2026-89698: Linux Vulnerability

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: widen nfsd_genl_rqstp address fields to sockaddr_storage struct nfsd_genl_rqstp declares rq_daddr and rq_saddr as plain "struct sockaddr" (16 bytes). When an IPv6 NFS client is connected, nfsd_genl_rpc_status_compose_msg() casts these fields to "struct sockaddr_in6 *" (28 bytes) and reads sin6_addr at offset 8..24, which extends 8 bytes past the end of the 16-byte sockaddr field into the adjacent rq_flags member. The 16-byte nla_put_in6_addr then ships 8 bytes of truncated IPv6 address followed by 8 bytes of rq_flags to userspace via the NFSD_A_RPC_STATUS_SADDR6/DADDR6 netlink attributes. This is reachable by any unprivileged process in the network namespace because NFSD_CMD_RPC_STATUS_GET uses GENL_CMD_CAP_DUMP without GENL_ADMIN_PERM. Fix by widening rq_daddr and rq_saddr to struct sockaddr_storage so the IPv6 casts operate within bounds, copying sizeof(struct sockaddr_storage) bytes in the memcpy calls so the full address is captured, and zero-initializing the genl_rqstp stack variable to prevent leaking uninitialized tail bytes through netlink.

Metrics

EPSS Probability

0.20%

9.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= bd9d6a3efa9709e653aafbeb859289feccb8e70c, < 9a2e791639a1c5cac3f219b0d2632835d8f88d27; >= bd9d6a3efa9709e653aafbeb859289feccb8e70c, < 03c512f22d3fbe7a3767d6df5e3d88b8e7c105e5; >= bd9d6a3efa9709e653aafbeb859289feccb8e70c, < dcb69ad0dafb4a24b825183bb94055d5be8a10bd; >= bd9d6a3efa9709e653aafbeb859289feccb8e70c, < a99d720ed2a5258564e5e9d5f39f3184a030d354
Linux	Linux	6.7

References

Timeline

Published: Sep 11, 2026
Last Modified: Sep 21, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-89698?

In the Linux kernel, the following vulnerability has been resolved: nfsd: widen nfsd_genl_rqstp address fields to sockaddr_storage struct nfsd_genl_rqstp declares rq_daddr and rq_saddr as plain "struct sockaddr" (16 bytes). When an IPv6 NFS client is connected, nfsd_genl_rpc_status_compose_msg() casts these fields to "struct sockaddr_in6 *" (28 bytes) and reads sin6_addr at offset 8..24, which extends 8 bytes past the end of the 16-byte sockaddr field into the adjacent rq_flags member. The 16-byte nla_put_in6_addr then ships 8 bytes of truncated IPv6 address followed by 8 bytes of rq_flags to userspace via the NFSD_A_RPC_STATUS_SADDR6/DADDR6 netlink attributes. This is reachable by any unprivileged process in the network namespace because NFSD_CMD_RPC_STATUS_GET uses GENL_CMD_CAP_DUMP without GENL_ADMIN_PERM. Fix by widening rq_daddr and rq_saddr to struct sockaddr_storage so the IPv6 casts operate within bounds, copying sizeof(struct sockaddr_storage) bytes in the memcpy calls so the full address is captured, and zero-initializing the genl_rqstp stack variable to prevent leaking uninitialized tail bytes through netlink.

How severe is CVE-2026-89698?

Severity scoring for CVE-2026-89698 is pending analysis. The EPSS model estimates a 0.20% probability of exploitation in the next 30 days.

How do I fix CVE-2026-89698?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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