CVE-2026-64025

Public on 2026-07-19
Modified on 2026-07-24
Description
In the Linux kernel, the following vulnerability has been resolved:

bpf, skmsg: fix verdict sk_data_ready racing with ktls rx

sk_psock_strp_data_ready() already checks tls_sw_has_ctx_rx() and
defers to psock->saved_data_ready when a TLS RX context is present,
avoiding a conflict with the TLS strparser's ownership of the receive
queue (commit e91de6afa81c, "bpf: Fix running sk_skb program types
with ktls").

sk_psock_verdict_data_ready() has no equivalent guard. When a socket
is inserted into a sockmap (BPF_SK_SKB_VERDICT) before TLS RX is
configured, tls_sw_strparser_arm() saves sk_psock_verdict_data_ready
as rx_ctx->saved_data_ready. On data arrival:

tls_data_ready -> tls_strp_data_ready -> tls_rx_msg_ready
-> saved_data_ready() = sk_psock_verdict_data_ready()
-> tcp_read_skb() drains sk_receive_queue via __skb_unlink()
without calling tcp_eat_skb(), so copied_seq is not advanced.

tls_strp_msg_load() then finds tcp_inq() >= full_len (stale), calls
tcp_recv_skb() on the now-empty queue, hits WARN_ON_ONCE(!first), and
returns with rx_ctx->strp.anchor.frag_list pointing at a psock-owned
(potentially freed) skb. tls_decrypt_sg() subsequently walks that
frag_list: use-after-free.

Apply the same fix as sk_psock_strp_data_ready(): if a TLS RX context
is present, call psock->saved_data_ready (sock_def_readable) to wake
recv() waiters and return immediately, leaving the receive queue
untouched. TLS retains sole ownership of the queue and decrypts the
record normally through tls_sw_recvmsg().
Severity
Important severity
Important
See what this means
CVSS v3 Base Score
7.0
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2 - Kernel-5.10 Extra kernel Pending Fix
Amazon Linux 2 - Kernel-5.15 Extra kernel Pending Fix
Amazon Linux 2 - Core kernel Not Affected
Amazon Linux 2 - Kernel-5.4 Extra kernel Not Affected
Amazon Linux 2023 kernel Pending Fix
Amazon Linux 2023 kernel6.12 2026-06-22 ALAS2023-2026-1894 Fixed
Amazon Linux 2023 kernel6.18 2026-06-22 ALAS2023-2026-1881 Fixed

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H