CVE-2026-74610 tls: don't leave a full plaintext sk_msg ring unpushed
An unprivileged user can cause a kernel NULL pointer dereference and system crash by triggering a specific TLS socket state via loopback TCP.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74610?
CVE-2026-74610 is a high-severity vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
tls: don't leave a full plaintext sk_msg ring unpushed
When the copy path in tls_sw_sendmsg_locked() adds the fragment that fills the plaintext sk_msg ring, it does not set full_record, so the record is left full and unpushed. A later splice() then adds to an already full ring: sk_msg_page_add() has no fullness check of its own, so sg.end wraps onto sg.start and the ring appears empty. Fragments added after that overwrite live entries, and sg.size no longer matches what is reachable between sg.start and sg.end, so pushing the record runs the scatterwalk off the end of the scatterlist.
An unprivileged user can trigger this on a loopback TCP socket with the "tls" ULP attached:
BUG: kernel NULL pointer dereference, address: 0000000000000008 RIP: 0010:memcpy_from_scatterwalk+0x32/0xc0 Call Trace: skcipher_walk_next+0x1d1/0x2c0 gcm_encrypt_aesni_avx+0x1e9/0x220 bpf_exec_tx_verdict+0x3bb/0x860 tls_sw_sendmsg+0xa1a/0xca0 __sys_sendto+0x1da/0x1f0
Set full_record in the copy path when the ring becomes full, and push a record that is already full on entry to the sendmsg loop.
Which versions are affected by CVE-2026-74610?
How do I fix CVE-2026-74610?
Apply the vendor's patch.
Is CVE-2026-74610 being exploited?
There is no known exploitation of CVE-2026-74610 in the wild and no public exploit code.
Sources
Also known as AZL-97047, BELL-CVE-2026-74610, DEBIAN-CVE-2026-74610, GHSA-mfgw-4w39-hh3m, UBUNTU-CVE-2026-74610.