CVE-2026-74589
bpf, sockmap: Fix sk_redir use-after-free in send verdict
Description
In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix sk_redir use-after-free in send verdict sk_psock_msg_verdict() takes a socket reference for psock->sk_redir. tcp_bpf_send_verdict() copies that pointer while holding the source socket lock, but does not take a reference for the local copy before dropping the lock around tcp_bpf_sendmsg_redir(). When apply_bytes keeps the cached verdict active, another sendmsg() on the same source socket can consume the remaining bytes and release the cached reference while the first thread still holds only the raw local pointer: CPU 0 CPU 1 sk_redir = psock->sk_redir apply_bytes remains nonzero release_sock(sk) lock_sock(sk) apply_bytes reaches zero psock->sk_redir = NULL release_sock(sk) tcp_bpf_sendmsg_redir(sk_redir) sock_put(sk_redir) tcp_bpf_sendmsg_redir(sk_redir) The final sock_put() can free sk_redir before CPU 0 dereferences it. KASAN reported: BUG: KASAN: slab-use-after-free in tcp_bpf_sendmsg_redir+0xf39/0x1020 Read of size 8 at addr ffff888108537090 by task poc/87 Call Trace: tcp_bpf_sendmsg_redir+0xf39/0x1020 tcp_bpf_sendmsg+0x977/0x1a50 __sys_sendto+0x32c/0x3a0 __x64_sys_sendto+0xdb/0x1b0 Allocated by task 85: sk_prot_alloc+0x56/0x210 sk_clone+0x6f/0x14b0 inet_csk_clone_lock+0x24/0x740 tcp_create_openreq_child+0x25/0x2710 tcp_v4_syn_recv_sock+0x10a/0xe00 Freed by task 0: __kasan_slab_free+0x43/0x70 slab_free_after_rcu_debug+0xa6/0x1e0 rcu_core+0x50a/0x1850 Last potentially related work creation: __sk_destruct+0x3da/0x540 sk_psock_destroy+0x81e/0xab0 process_one_work+0x63a/0x1070 Take a temporary socket reference while the source socket lock still protects psock->sk_redir, and drop it after tcp_bpf_sendmsg_redir() returns. This keeps each unlocked use independent of cached-verdict ownership.
INFO
Published Date :
Aug. 22, 2026, 4:16 p.m.
Last Modified :
Aug. 22, 2026, 4:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Take a temporary socket reference early.
- Drop the reference after tcp_bpf_sendmsg_redir returns.
- Apply kernel updates to resolve the issue.
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associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
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approaches employed by adversaries to exploit the CVE-2026-74589
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-74589 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-74589 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 22, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': '41b7da0cb72ca5aa1e62b68dab323d0791fc6bdf', 'versionType': 'git'}, {'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': '9b4fbc371a6ecf1b4e43b5a629015cc0830d8de3', 'versionType': 'git'}, {'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': '90a19b0894ba79a699b48cf44421b36fbd566e99', 'versionType': 'git'}, {'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': 'd192cff2a37d59206dabe6ec2e60ceac6271f274', 'versionType': 'git'}, {'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': '4c9d9aa809c261dc0490a0e19d675f7e8e4c85bf', 'versionType': 'git'}, {'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': 'a14e4ef1d90c3418f01b3b6b8fd3a40a0a208a10', 'versionType': 'git'}, {'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': '1cec526cf0a2227395f2c2f4b671cb052ff0b00e', 'versionType': 'git'}, {'status': 'affected', 'version': '604326b41a6fb9b4a78b6179335decee0365cd8c', 'lessThan': 'a76624733730e541e4955fdecf506af2f6b20558', 'versionType': 'git'}], 'programFiles': ['net/ipv4/tcp_bpf.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.20'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.20', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.265', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.216', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.183', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.152', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.104', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.45', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.9', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ipv4/tcp_bpf.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix sk_redir use-after-free in send verdict sk_psock_msg_verdict() takes a socket reference for psock->sk_redir. tcp_bpf_send_verdict() copies that pointer while holding the source socket lock, but does not take a reference for the local copy before dropping the lock around tcp_bpf_sendmsg_redir(). When apply_bytes keeps the cached verdict active, another sendmsg() on the same source socket can consume the remaining bytes and release the cached reference while the first thread still holds only the raw local pointer: CPU 0 CPU 1 sk_redir = psock->sk_redir apply_bytes remains nonzero release_sock(sk) lock_sock(sk) apply_bytes reaches zero psock->sk_redir = NULL release_sock(sk) tcp_bpf_sendmsg_redir(sk_redir) sock_put(sk_redir) tcp_bpf_sendmsg_redir(sk_redir) The final sock_put() can free sk_redir before CPU 0 dereferences it. KASAN reported: BUG: KASAN: slab-use-after-free in tcp_bpf_sendmsg_redir+0xf39/0x1020 Read of size 8 at addr ffff888108537090 by task poc/87 Call Trace: tcp_bpf_sendmsg_redir+0xf39/0x1020 tcp_bpf_sendmsg+0x977/0x1a50 __sys_sendto+0x32c/0x3a0 __x64_sys_sendto+0xdb/0x1b0 Allocated by task 85: sk_prot_alloc+0x56/0x210 sk_clone+0x6f/0x14b0 inet_csk_clone_lock+0x24/0x740 tcp_create_openreq_child+0x25/0x2710 tcp_v4_syn_recv_sock+0x10a/0xe00 Freed by task 0: __kasan_slab_free+0x43/0x70 slab_free_after_rcu_debug+0xa6/0x1e0 rcu_core+0x50a/0x1850 Last potentially related work creation: __sk_destruct+0x3da/0x540 sk_psock_destroy+0x81e/0xab0 process_one_work+0x63a/0x1070 Take a temporary socket reference while the source socket lock still protects psock->sk_redir, and drop it after tcp_bpf_sendmsg_redir() returns. This keeps each unlocked use independent of cached-verdict ownership. Added Reference https://git.kernel.org/stable/c/1cec526cf0a2227395f2c2f4b671cb052ff0b00e Added Reference https://git.kernel.org/stable/c/41b7da0cb72ca5aa1e62b68dab323d0791fc6bdf Added Reference https://git.kernel.org/stable/c/4c9d9aa809c261dc0490a0e19d675f7e8e4c85bf Added Reference https://git.kernel.org/stable/c/90a19b0894ba79a699b48cf44421b36fbd566e99 Added Reference https://git.kernel.org/stable/c/9b4fbc371a6ecf1b4e43b5a629015cc0830d8de3 Added Reference https://git.kernel.org/stable/c/a14e4ef1d90c3418f01b3b6b8fd3a40a0a208a10 Added Reference https://git.kernel.org/stable/c/a76624733730e541e4955fdecf506af2f6b20558 Added Reference https://git.kernel.org/stable/c/d192cff2a37d59206dabe6ec2e60ceac6271f274