Use After Free

In the Linux kernel, the following vulnerability has been resolved: net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs When shrinking the number of real tx queues, netif_set_real_num_tx_queues() calls qdisc_reset_all_tx_gt() to flush qdiscs for queues which will no longer be used. qdisc_reset_all_tx_gt() currently serializes qdisc_reset() with qdisc_lock(). However, for lockless qdiscs, the dequeue path is serialized by qdisc_run_begin/end() using qdisc->seqlock instead, so qdisc_reset() can run concurrently with __qdisc_run() and free skbs while they are still being dequeued, leading to UAF. This can easily be reproduced on e.g. virtio-net by imposing heavy traffic while frequently changing the number of queue pairs: iperf3 -ub0 -c $peer -t 0 & while :; do ethtool -L eth0 combined 1 ethtool -L eth0 combined 2 done With KASAN enabled, this leads to reports like: BUG: KASAN: slab-use-after-free in __qdisc_run+0x133f/0x1760 ... Call Trace: <TASK> ... __qdisc_run+0x133f/0x1760 __dev_queue_xmit+0x248f/0x3550 ip_finish_output2+0xa42/0x2110 ip_output+0x1a7/0x410 ip_send_skb+0x2e6/0x480 udp_send_skb+0xb0a/0x1590 udp_sendmsg+0x13c9/0x1fc0 ... </TASK> Allocated by task 1270 on cpu 5 at 44.558414s: ... alloc_skb_with_frags+0x84/0x7c0 sock_alloc_send_pskb+0x69a/0x830 __ip_append_data+0x1b86/0x48c0 ip_make_skb+0x1e8/0x2b0 udp_sendmsg+0x13a6/0x1fc0 ... Freed by task 1306 on cpu 3 at 44.558445s: ... kmem_cache_free+0x117/0x5e0 pfifo_fast_reset+0x14d/0x580 qdisc_reset+0x9e/0x5f0 netif_set_real_num_tx_queues+0x303/0x840 virtnet_set_channels+0x1bf/0x260 [virtio_net] ethnl_set_channels+0x684/0xae0 ethnl_default_set_doit+0x31a/0x890 ... Serialize qdisc_reset_all_tx_gt() against the lockless dequeue path by taking qdisc->seqlock for TCQ_F_NOLOCK qdiscs, matching the serialization model already used by dev_reset_queue(). Additionally clear QDISC_STATE_NON_EMPTY after reset so the qdisc state reflects an empty queue, avoiding needless re-scheduling.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: cancel rfkill_block work in wiphy_unregister() There is a use-after-free error in cfg80211_shutdown_all_interfaces found by syzkaller: BUG: KASAN: use-after-free in cfg80211_shutdown_all_interfaces+0x213/0x220 Read of size 8 at addr ffff888112a78d98 by task kworker/0:5/5326 CPU: 0 UID: 0 PID: 5326 Comm: kworker/0:5 Not tainted 6.19.0-rc2 #2 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: events cfg80211_rfkill_block_work Call Trace: <TASK> dump_stack_lvl+0x116/0x1f0 print_report+0xcd/0x630 kasan_report+0xe0/0x110 cfg80211_shutdown_all_interfaces+0x213/0x220 cfg80211_rfkill_block_work+0x1e/0x30 process_one_work+0x9cf/0x1b70 worker_thread+0x6c8/0xf10 kthread+0x3c5/0x780 ret_from_fork+0x56d/0x700 ret_from_fork_asm+0x1a/0x30 </TASK> The problem arises due to the rfkill_block work is not cancelled when wiphy is being unregistered. In order to fix the issue cancel the corresponding work in wiphy_unregister(). Found by Linux Verification Center (linuxtesting.org) with Syzkaller.Show less

In the Linux kernel, the following vulnerability has been resolved: ipmi: Fix use-after-free and list corruption on sender error The analysis from Breno: When the SMI sender returns an error, smi_work() delivers an error response but then jumps back to restart without cleaning up properly: 1. intf->curr_msg is not cleared, so no new message is pulled 2. newmsg still points to the message, causing sender() to be called again with the same message 3. If sender() fails again, deliver_err_response() is called with the same recv_msg that was already queued for delivery This causes list_add corruption ("list_add double add") because the recv_msg is added to the user_msgs list twice. Subsequently, the corrupted list leads to use-after-free when the memory is freed and reused, and eventually a NULL pointer dereference when accessing recv_msg->done. The buggy sequence: sender() fails -> deliver_err_response(recv_msg) // recv_msg queued for delivery -> goto restart // curr_msg not cleared! sender() fails again (same message!) -> deliver_err_response(recv_msg) // tries to queue same recv_msg -> LIST CORRUPTION Fix this by freeing the message and setting it to NULL on a send error. Also, always free the newmsg on a send error, otherwise it will leak.Show less

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a UAF issue in bpf_trampoline_link_cgroup_shim The root cause of this bug is that when 'bpf_link_put' reduces the refcount of 'shim_link->link.link' to zero, the resource is considered released but may still be referenced via 'tr->progs_hlist' in 'cgroup_shim_find'. The actual cleanup of 'tr->progs_hlist' in 'bpf_shim_tramp_link_release' is deferred. During this window, another process can cause a use-after-free via 'bpf_trampoline_link_cgroup_shim'. Based on Martin KaFai Lau's suggestions, I have created a simple patch. To fix this: Add an atomic non-zero check in 'bpf_trampoline_link_cgroup_shim'. Only increment the refcount if it is not already zero. Testing: I verified the fix by adding a delay in 'bpf_shim_tramp_link_release' to make the bug easier to trigger: static void bpf_shim_tramp_link_release(struct bpf_link *link) { /* ... */ if (!shim_link->trampoline) return; + msleep(100); WARN_ON_ONCE(bpf_trampoline_unlink_prog(&shim_link->link, shim_link->trampoline, NULL)); bpf_trampoline_put(shim_link->trampoline); } Before the patch, running a PoC easily reproduced the crash(almost 100%) with a call trace similar to KaiyanM's report. After the patch, the bug no longer occurs even after millions of iterations.Show less

In the Linux kernel, the following vulnerability has been resolved: scsi: pm8001: Fix use-after-free in pm8001_queue_command() Commit e29c47fe8946 ("scsi: pm8001: Simplify pm8001_task_exec()") refactors pm8001_queue_command(), however it introduces a potential cause of a double free scenario when it changes the function to return -ENODEV in case of phy down/device gone state. In this path, pm8001_queue_command() updates task status and calls task_done to indicate to upper layer that the task has been handled. However, this also frees the underlying SAS task. A -ENODEV is then returned to the caller. When libsas sas_ata_qc_issue() receives this error value, it assumes the task wasn't handled/queued by LLDD and proceeds to clean up and free the task again, resulting in a double free. Since pm8001_queue_command() handles the SAS task in this case, it should return 0 to the caller indicating that the task has been handled.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: libertas: fix use-after-free in lbs_free_adapter() The lbs_free_adapter() function uses timer_delete() (non-synchronous) for both command_timer and tx_lockup_timer before the structure is freed. This is incorrect because timer_delete() does not wait for any running timer callback to complete. If a timer callback is executing when lbs_free_adapter() is called, the callback will access freed memory since lbs_cfg_free() frees the containing structure immediately after lbs_free_adapter() returns. Both timer callbacks (lbs_cmd_timeout_handler and lbs_tx_lockup_handler) access priv->driver_lock, priv->cur_cmd, priv->dev, and other fields, which would all be use-after-free violations. Use timer_delete_sync() instead to ensure any running timer callback has completed before returning. This bug was introduced in commit 8f641d93c38a ("libertas: detect TX lockups and reset hardware") where del_timer() was used instead of del_timer_sync() in the cleanup path. The command_timer has had the same issue since the driver was first written.Show less

A use-after-free issue was addressed with improved memory management. This issue is fixed in iOS 18.7.7 and iPadOS 18.7.7, iOS 26.4 and iPadOS 26.4, macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, macOS Tahoe 26.4, tvOS 26.4, visionOS 26.4, watchOS 26.4. Processing maliciously crafted web content may lead to an unexpected process crash.Show less

The issue was addressed with improved memory handling. This issue is fixed in Safari 26.4, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, tvOS 26.4, visionOS 26.4, watchOS 26.4. A malicious website may be able to process restricted web content outside the sandbox.Show less

The issue was addressed with improved memory handling. This issue is fixed in Safari 26.4, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, visionOS 26.4. Processing maliciously crafted web content may lead to an unexpected process crash.Show less

A use-after-free issue was addressed with improved memory management. This issue is fixed in macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, macOS Tahoe 26.4. Mounting a maliciously crafted SMB network share may lead to system termination.Show less

A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.7.7 and iPadOS 18.7.7, iOS 26.4 and iPadOS 26.4, macOS Sequoia 15.7.5, macOS Tahoe 26.4, tvOS 26.4, watchOS 26.4. An app may be able to cause unexpected system termination or write kernel memory.Show less

A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.7.7 and iPadOS 18.7.7, iOS 26.3 and iPadOS 26.3, macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, macOS Tahoe 26.3, tvOS 26.3, visionOS 26.3, watchOS 26.3. An app may be able to cause unexpected system termination.Show less