critical CVSS 9.8

CVE-2026-64025·Kernel vulnerability

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
critical
Software
Kernel
Fixed in
7.0.11
Published

Affected versions

From: 6.19

Until: 7.0.11

Fixed in: 7.0.11

How to fix this CVE

Update your Linux kernel to version 7.0.11 or later to resolve a critical race condition between BPF socket message verdict handlers and kernel TLS receive operations. This vulnerability allows a use-after-free condition when sockets are managed by BPF programs while TLS is enabled, potentially leading to kernel memory corruption. Applying the kernel security patch immediately is essential for systems running affected versions.

sudo dnf update kernel kernel-devel

Defensia detects this vulnerability

How to check if you are affected

  1. Step 1: Check your kernel version with `uname -r` and verify if it falls in the vulnerable range (6.19 to 7.0.10)
  2. Step 2: Verify if BPF socket programs (BPF_SK_SKB_VERDICT) are loaded by running `bpftool prog list | grep sk_skb`
  3. Step 3: Check if kernel TLS (ktls) is in use by inspecting `/sys/module/tls/` or running `lsmod | grep tls`
  4. Step 4: After patching, confirm the new kernel version with `uname -r` and verify it is 7.0.11 or later, then reboot if necessary

FAQ

What is CVE-2026-64025?

This vulnerability is a use-after-free condition in the Linux kernel that occurs when BPF socket message verdict handlers (BPF_SK_SKB_VERDICT) interact improperly with kernel TLS receive operations, allowing an attacker to access freed memory and potentially execute arbitrary kernel code.

Is CVE-2026-64025 being actively exploited?

No, according to CISA's Known Exploited Vulnerabilities (KEV) catalog, this vulnerability is not currently being actively exploited in the wild, and no public exploit code has been disclosed.

What versions of Kernel are affected by CVE-2026-64025?

Linux kernel versions 6.19 through 7.0.10 are affected; version 7.0.11 and later contain the security fix.

How do I check if my server is vulnerable to CVE-2026-64025?

Run `uname -r` to check your kernel version; if it reports a version between 6.19 and 7.0.10, your system is vulnerable. Additionally, confirm that BPF socket programs and kernel TLS are both in use on your system.

Does Defensia detect CVE-2026-64025?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2026-64025 will appear in your dashboard with remediation steps.

Related Kernel CVEs

CVE-2026-63795CVSS 10In the Linux kernel, the following vulnerability has been resolved: 9p: avoid putting oldfid in p9_client_walk() error path When p9_client_walk() is called with clone set to false, fid aliases oldfid. If the walk subsequently fails after the request has been sent, the error path jumps to clunk_fid, which currently calls p9_fid_put(fid) unconditionally. This drops a reference to oldfid even though ownership of oldfid remains with the caller. If this is the last reference, oldfid can be clunked and destroyed while the caller still expects it to be valid. A later use or put of oldfid can then trigger a use-after-free or refcount underflow. Fix this by only putting fid in the clunk_fid error path when it does not alias oldfid, matching the existing guard in the error path below. This can be triggered when a multi-component walk is split into multiple p9_client_walk() calls and a later non-cloning walk fails. A reproducer and refcount warning logs are available on request.
CVE-2026-53260CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: tcp: Add preempt_{disable,enable}_nested() in reqsk_queue_hash_req(). syzbot reported a weird reqsk->rsk_refcnt underflow in __inet_csk_reqsk_queue_drop(). The captured reqsk_put() in __inet_csk_reqsk_queue_drop() is called only when it successfully removes reqsk from ehash. Moreover, reqsk_timer_handler() calls another reqsk_put() after that. This indicates that the reqsk was missing both refcnts for ehash and the timer itself. Since all the syzbot reports had PREEMPT_RT enabled, the only possible scenario is that reqsk_queue_hash_req() is preempted after mod_timer() and before refcount_set(), and then the timer triggered after 1s aborts the reqsk due to its listener's close(). Let's wrap mod_timer() and refcount_set() with preempt_disable_nested() and preempt_enable_nested(). Note that inet_ehash_insert() holds the normal spin_lock() (mutex in PREEMPT_RT), so it must be called outside of preempt_disable_nested(), but this is fine. The lookup path just ignores 0 sk_refcnt entries in ehash and tries to create another reqsk, but this will fail at inet_ehash_insert(). [0]: refcount_t: underflow; use-after-free. WARNING: lib/refcount.c:28 at refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28, CPU#0: ktimers/0/16 Modules linked in: CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:refcount_warn_saturate+0xb2/0x110 lib/refcount.c:28 Code: e4 7d d1 0a 67 48 0f b9 3a eb 4a e8 38 3d 23 fd 48 8d 3d e1 7d d1 0a 67 48 0f b9 3a eb 37 e8 25 3d 23 fd 48 8d 3d de 7d d1 0a <67> 48 0f b9 3a eb 24 e8 12 3d 23 fd 48 8d 3d db 7d d1 0a 67 48 0f RSP: 0000:ffffc90000157948 EFLAGS: 00010246 RAX: ffffffff84a1301b RBX: 0000000000000003 RCX: ffff88801ca98000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: ffffffff8f72ae00 RBP: ffffffff99ae3b01 R08: ffff88801ca98000 R09: 0000000000000005 R10: 0000000000000100 R11: 0000000000000004 R12: ffff8880425ef568 R13: ffff8880425ef4f8 R14: ffff8880425ef578 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126386000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7b46710e9c CR3: 000000000dbb6000 CR4: 00000000003526f0 Call Trace: <TASK> __refcount_sub_and_test include/linux/refcount.h:400 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] reqsk_put include/net/request_sock.h:136 [inline] __inet_csk_reqsk_queue_drop+0x3ce/0x440 net/ipv4/inet_connection_sock.c:1007 reqsk_timer_handler+0x651/0xdf0 net/ipv4/inet_connection_sock.c:1137 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1799 [inline] __run_timers kernel/time/timer.c:2374 [inline] __run_timer_base+0x6a3/0x9f0 kernel/time/timer.c:2386 run_timer_base kernel/time/timer.c:2395 [inline] run_timer_softirq+0x67/0x170 kernel/time/timer.c:2403 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0x69/0x100 kernel/softirq.c:1151 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK>
CVE-2026-64162CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: idpf: fix read_dev_clk_lock spinlock init in idpf_ptp_init() In idpf_ptp_init(), read_dev_clk_lock is initialized after ptp_schedule_worker() had already been called (and after idpf_ptp_settime64() could reach the lock). The PTP aux worker fires immediately upon scheduling and can call into idpf_ptp_read_src_clk_reg_direct(), which takes spin_lock(&ptp->read_dev_clk_lock) on an uninitialized lock, triggering the lockdep "non-static key" warning: [12973.796587] idpf 0000:83:00.0: Device HW Reset initiated [12974.094507] INFO: trying to register non-static key. ... [12974.097208] Call Trace: [12974.097213] <TASK> [12974.097218] dump_stack_lvl+0x93/0xe0 [12974.097234] register_lock_class+0x4c4/0x4e0 [12974.097249] ? __lock_acquire+0x427/0x2290 [12974.097259] __lock_acquire+0x98/0x2290 [12974.097272] lock_acquire+0xc6/0x310 [12974.097281] ? idpf_ptp_read_src_clk_reg+0xb7/0x150 [idpf] [12974.097311] ? lockdep_hardirqs_on_prepare+0xde/0x190 [12974.097318] ? finish_task_switch.isra.0+0xd2/0x350 [12974.097330] ? __pfx_ptp_aux_kworker+0x10/0x10 [ptp] [12974.097343] _raw_spin_lock+0x30/0x40 [12974.097353] ? idpf_ptp_read_src_clk_reg+0xb7/0x150 [idpf] [12974.097373] idpf_ptp_read_src_clk_reg+0xb7/0x150 [idpf] [12974.097391] ? kthread_worker_fn+0x88/0x3d0 [12974.097404] ? kthread_worker_fn+0x4e/0x3d0 [12974.097411] idpf_ptp_update_cached_phctime+0x26/0x120 [idpf] [12974.097428] ? _raw_spin_unlock_irq+0x28/0x50 [12974.097436] idpf_ptp_do_aux_work+0x15/0x20 [idpf] [12974.097454] ptp_aux_kworker+0x20/0x40 [ptp] [12974.097464] kthread_worker_fn+0xd5/0x3d0 [12974.097474] ? __pfx_kthread_worker_fn+0x10/0x10 [12974.097482] kthread+0xf4/0x130 [12974.097489] ? __pfx_kthread+0x10/0x10 [12974.097498] ret_from_fork+0x32c/0x410 [12974.097512] ? __pfx_kthread+0x10/0x10 [12974.097519] ret_from_fork_asm+0x1a/0x30 [12974.097540] </TASK> Move the call to spin_lock_init() up a bit to make sure read_dev_clk_lock is not touched before it's been initialized.
CVE-2026-52982CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: net: usb: rtl8150: fix use-after-free in rtl8150_start_xmit() syzbot reported a KASAN slab-use-after-free read in rtl8150_start_xmit() when accessing skb->len for tx statistics after usb_submit_urb() has been called: BUG: KASAN: slab-use-after-free in rtl8150_start_xmit+0x71f/0x760 drivers/net/usb/rtl8150.c:712 Read of size 4 at addr ffff88810eb7a930 by task kworker/0:4/5226 The URB completion handler write_bulk_callback() frees the skb via dev_kfree_skb_irq(dev->tx_skb). The URB may complete on another CPU in softirq context before usb_submit_urb() returns in the submitter, so by the time the submitter reads skb->len the skb has already been queued to the per-CPU completion_queue and freed by net_tx_action(): CPU A (xmit) CPU B (USB completion softirq) ------------ ------------------------------ dev->tx_skb = skb; usb_submit_urb() --+ |-------> write_bulk_callback() | dev_kfree_skb_irq(dev->tx_skb) | net_tx_action() | napi_skb_cache_put() <-- free netdev->stats.tx_bytes | += skb->len; <-- UAF read Fix it by caching skb->len before submitting the URB and using the cached value when updating the tx_bytes counter. The pre-existing tx_bytes semantics are preserved: the counter tracks the original frame length (skb->len), not the ETH_ZLEN/USB-alignment padded "count" value that is handed to the device. Changing that would be a user-visible accounting change and is out of scope for this UAF fix.
CVE-2026-53246CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing When a listening SCTP server processes a COOKIE_ECHO chunk, the cached peer INIT chunk embedded after the cookie is parsed and its parameters are later walked by sctp_process_init() using sctp_walk_params(). However, the chunk header length of this cached INIT chunk was not validated against the remaining buffer in the COOKIE_ECHO payload. If the length field is inflated, the parameter walk can run beyond the actual received data, leading to out-of-bounds reads and potential memory corruption during later parameter handling (e.g. STATE_COOKIE processing and kmemdup() copies). Add a bounds check in sctp_unpack_cookie() to ensure the cached INIT chunk length does not exceed the available data in the COOKIE_ECHO buffer before it is used.

References

Track CVEs across your fleet automatically

Defensia scans your Linux servers and tells you exactly which ones are running vulnerable versions — including CVE-2026-64025. Free for 1 server.

Get started free