# CVE-2022-49973: skmsg: Fix wrong last sg check in sk_msg_recvmsg()

Status: published. Published: 2025-06-18. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

skmsg: Fix wrong last sg check in sk_msg_recvmsg()

Fix one kernel NULL pointer dereference as below:

[  224.462334] Call Trace:
[  224.462394]  __tcp_bpf_recvmsg+0xd3/0x380
[  224.462441]  ? sock_has_perm+0x78/0xa0
[  224.462463]  tcp_bpf_recvmsg+0x12e/0x220
[  224.462494]  inet_recvmsg+0x5b/0xd0
[  224.462534]  __sys_recvfrom+0xc8/0x130
[  224.462574]  ? syscall_trace_enter+0x1df/0x2e0
[  224.462606]  ? __do_page_fault+0x2de/0x500
[  224.462635]  __x64_sys_recvfrom+0x24/0x30
[  224.462660]  do_syscall_64+0x5d/0x1d0
[  224.462709]  entry_SYSCALL_64_after_hwframe+0x65/0xca

In commit 9974d37ea75f ("skmsg: Fix invalid last sg check in
sk_msg_recvmsg()"), we change last sg check to sg_is_last(),
but in sockmap redirection case (without stream_parser/stream_verdict/
skb_verdict), we did not mark the end of the scatterlist. Check the
sk_msg_alloc, sk_msg_page_add, and bpf_msg_push_data functions, they all
do not mark the end of sg. They are expected to use sg.end for end
judgment. So the judgment of '(i != msg_rx->sg.end)' is added back here.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 293c53b7dbf9073cbcc488f938bc053ff4caeec0; < de22cba333d8699ad77e79f862fe1320cb1284de (affected, git); ≥ 1295dae30f30c3daa03005ed8958d44b17f037fd; < 10ee118a1756141f8e9c87aa7344ed12b41630a8 (affected, git); ≥ 9974d37ea75f01b47d16072b5dad305bd8d23fcc; < 583585e48d965338e73e1eb383768d16e0922d73 (affected, git); 4674c0da448b546e390a981b819cd4af5cb16cf9 (affected, git); ≥ 5.18.18; < 5.19 (affected, semver). Source: CNA: Linux
- Linux / Linux: ≥ 5.15.61; < 5.15.66 (affected, semver); ≥ 5.19.2; < 5.19.8 (affected, semver). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.24% as of 2026-11-05; percentile 15.53%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/de22cba333d8699ad77e79f862fe1320cb1284de (CNA: Linux)

- https://git.kernel.org/stable/c/10ee118a1756141f8e9c87aa7344ed12b41630a8 (CNA: Linux)

- https://git.kernel.org/stable/c/583585e48d965338e73e1eb383768d16e0922d73 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2022-49973; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2022-49973; retrieved 2026-11-05; source updated Not reported

Revision: 3306e08f62c6645107936137515a5d7e94b54f9d3e56b3ae30de22f80fa0c713

Canonical: https://y2.dev/cve/CVE-2022-49973

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