Linux: >> Linux Kernel >> 5.15.152 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
PCI: use generic driver_override infrastructure
When a driver is probed through __driver_attach(), the bus' match()
callback is called without the device lock held, thus accessing the
driver_override field without a lock, which can cause a UAF.
Fix this by using the driver-core driver_override infrastructure taking
care of proper locking internally.
Note that calling match() from __driver_attach() without the device lock
held is intentional. [1]
CVSS Score
7.8
EPSS Score
0.002
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix deadlock between reflink and transaction commit when using flushoncommit
When using the flushoncommit mount option, we can have a deadlock between
a transaction commit and a reflink operation that copied an inline extent
to an offset beyond the current i_size of the destination node.
The deadlock happens like this:
1) Task A clones an inline extent from inode X to an offset of inode Y
that is beyond Y's current i_size. This means we copied the inline
extent's data to a folio of inode Y that is beyond its EOF, using a
call to copy_inline_to_page();
2) Task B starts a transaction commit and calls
btrfs_start_delalloc_flush() to flush delalloc;
3) The delalloc flushing sees the new dirty folio of inode Y and when it
attempts to flush it, it ends up at extent_writepage() and sees that
the offset of the folio is beyond the i_size of inode Y, so it attempts
to invalidate the folio by calling folio_invalidate(), which ends up at
btrfs' folio invalidate callback - btrfs_invalidate_folio(). There it
tries to lock the folio's range in inode Y's extent io tree, but it
blocks since it's currently locked by task A - during a reflink we lock
the inodes and the source and destination ranges after flushing all
delalloc and waiting for ordered extent completion - after that we
don't expect to have dirty folios in the ranges, the exception is if
we have to copy an inline extent's data (because the destination offset
is not zero);
4) Task A then attempts to start a transaction to update the inode item,
and then it's blocked since the current transaction is in the
TRANS_STATE_COMMIT_START state. Therefore task A has to wait for the
current transaction to become unblocked (its state >=
TRANS_STATE_UNBLOCKED).
So task A is waiting for the transaction commit done by task B, and
the later waiting on the extent lock of inode Y that is currently
held by task A.
Syzbot recently reported this with the following stack traces:
INFO: task kworker/u8:7:1053 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:7 state:D stack:23520 pid:1053 tgid:1053 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-btrfs-46)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
wait_extent_bit fs/btrfs/extent-io-tree.c:811 [inline]
btrfs_lock_extent_bits+0x59c/0x700 fs/btrfs/extent-io-tree.c:1914
btrfs_lock_extent fs/btrfs/extent-io-tree.h:152 [inline]
btrfs_invalidate_folio+0x43d/0xc40 fs/btrfs/inode.c:7704
extent_writepage fs/btrfs/extent_io.c:1852 [inline]
extent_write_cache_pages fs/btrfs/extent_io.c:2580 [inline]
btrfs_writepages+0x12ff/0x2440 fs/btrfs/extent_io.c:2713
do_writepages+0x32e/0x550 mm/page-writeback.c:2554
__writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750
writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2042
wb_writeback+0x456/0xb70 fs/fs-writeback.c:2227
wb_do_writeback fs/fs-writeback.c:2374 [inline]
wb_workfn+0x41a/0xf60 fs/fs-writeback.c:2414
process_one_work kernel/workqueue.c:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task syz.4.64:6910 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.64 state:D stack:22752 pid:6910 tgid:
---truncated---
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
powerpc/64s: Fix unmap race with PMD migration entries
The following race is possible with migration swap entries or
device-private THP entries. e.g. when move_pages is called on a PMD THP
page, then there maybe an intermediate state, where PMD entry acts as
a migration swap entry (pmd_present() is true). Then if an munmap
happens at the same time, then this VM_BUG_ON() can happen in
pmdp_huge_get_and_clear_full().
This patch fixes that.
Thread A: move_pages() syscall
add_folio_for_migration()
mmap_read_lock(mm)
folio_isolate_lru(folio)
mmap_read_unlock(mm)
do_move_pages_to_node()
migrate_pages()
try_to_migrate_one()
spin_lock(ptl)
set_pmd_migration_entry()
pmdp_invalidate() # PMD: _PAGE_INVALID | _PAGE_PTE | pfn
set_pmd_at() # PMD: migration swap entry (pmd_present=0)
spin_unlock(ptl)
[page copy phase] # <--- RACE WINDOW -->
Thread B: munmap()
mmap_write_downgrade(mm)
unmap_vmas() -> zap_pmd_range()
zap_huge_pmd()
__pmd_trans_huge_lock()
pmd_is_huge(): # !pmd_present && !pmd_none -> TRUE (swap entry)
pmd_lock() -> # spin_lock(ptl), waits for Thread A to release ptl
pmdp_huge_get_and_clear_full()
VM_BUG_ON(!pmd_present(*pmdp)) # HITS!
[ 287.738700][ T1867] ------------[ cut here ]------------
[ 287.743843][ T1867] kernel BUG at arch/powerpc/mm/book3s64/pgtable.c:187!
cpu 0x0: Vector: 700 (Program Check) at [c00000044037f4f0]
pc: c000000000094ca4: pmdp_huge_get_and_clear_full+0x6c/0x23c
lr: c000000000645dec: zap_huge_pmd+0xb0/0x868
sp: c00000044037f790
msr: 800000000282b033
current = 0xc0000004032c1a00
paca = 0xc000000004fe0000 irqmask: 0x03 irq_happened: 0x09
pid = 1867, comm = a.out
kernel BUG at :187!
Linux version 6.19.0-12136-g14360d4f917c-dirty (powerpc64le-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #27 SMP PREEMPT Sun Feb 22 10:38:56 IST 2026
enter ? for help
[link register ] c000000000645dec zap_huge_pmd+0xb0/0x868
[c00000044037f790] c00000044037f7d0 (unreliable)
[c00000044037f7d0] c000000000645dcc zap_huge_pmd+0x90/0x868
[c00000044037f840] c0000000005724cc unmap_page_range+0x176c/0x1f40
[c00000044037fa00] c000000000572ea0 unmap_vmas+0xb0/0x1d8
[c00000044037fa90] c0000000005af254 unmap_region+0xb4/0x128
[c00000044037fb50] c0000000005af400 vms_complete_munmap_vmas+0x138/0x310
[c00000044037fbe0] c0000000005b0f1c do_vmi_align_munmap+0x1ec/0x238
[c00000044037fd30] c0000000005b3688 __vm_munmap+0x170/0x1f8
[c00000044037fdf0] c000000000587f74 sys_munmap+0x2c/0x40
[c00000044037fe10] c000000000032668 system_call_exception+0x128/0x350
[c00000044037fe50] c00000000000d05c system_call_vectored_common+0x15c/0x2ec
---- Exception: 3000 (System Call Vectored) at 0000000010064a2c
SP (7fff9b1ee9c0) is in userspace
0:mon> zh
commit a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages"),
enabled migration for device-private PMD entries. Hence this is one
other path where this warning could get trigger from.
------------[ cut here ]------------
WARNING: arch/powerpc/mm/book3s64/hash_pgtable.c:199 at hash__pmd_hugepage_update+0x48/0x284, CPU#3: hmm-tests/1905
Modules linked in: test_hmm
CPU: 3 UID: 0 PID: 1905 Comm: hmm-tests Tainted: G B W L N 7.0.0-rc1-01438-g7e2f0ee7581c #21 PREEMPT
Tainted: [B]=BAD_PAGE, [W]=WARN, [L]=SOFTLOCKUP, [N]=TEST
Hardware name: IBM pSeries (emulated by qemu) POWER10 (architected) 0x801200 0xf000006 of:SLOF,git-ee03ae pSeries
NIP [c000000000096b70] hash__pmd_hugepage_update+0x48/0x284
LR [c000000000096e7c] hash__pmdp_huge_get_and_clear+0xd0/0xd4
Call Trace:
[c000000604707670] [c000000004e102b8] 0xc000000004e102b8 (unreliable)
[c000000604707700] [c00000000064ec3c] set_pmd_migration_entry+0x414/0x498
[c000000604707760] [c00000000063e5a4] migrate_vma_col
---truncated---
CVSS Score
4.7
EPSS Score
0.002
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
bpf: test_run: Fix the null pointer dereference issue in bpf_lwt_xmit_push_encap
The bpf_lwt_xmit_push_encap helper needs to access skb_dst(skb)->dev to
calculate the needed headroom:
err = skb_cow_head(skb,
len + LL_RESERVED_SPACE(skb_dst(skb)->dev));
But skb->_skb_refdst may not be initialized when the skb is set up by
bpf_prog_test_run_skb function. Executing bpf_lwt_push_ip_encap function
in this scenario will trigger null pointer dereference, causing a kernel
crash as Yinhao reported:
[ 105.186365] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 105.186382] #PF: supervisor read access in kernel mode
[ 105.186388] #PF: error_code(0x0000) - not-present page
[ 105.186393] PGD 121d3d067 P4D 121d3d067 PUD 106c83067 PMD 0
[ 105.186404] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 105.186412] CPU: 3 PID: 3250 Comm: poc Kdump: loaded Not tainted 6.19.0-rc5 #1
[ 105.186423] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 105.186427] RIP: 0010:bpf_lwt_push_ip_encap+0x1eb/0x520
[ 105.186443] Code: 0f 84 de 01 00 00 0f b7 4a 04 66 85 c9 0f 85 47 01 00 00 31 c0 5b 5d 41 5c 41 5d 41 5e c3 cc cc cc cc 48 8b 73 58 48 83 e6 fe <48> 8b 36 0f b7 be ec 00 00 00 0f b7 b6 e6 00 00 00 01 fe 83 e6 f0
[ 105.186449] RSP: 0018:ffffbb0e0387bc50 EFLAGS: 00010246
[ 105.186455] RAX: 000000000000004e RBX: ffff94c74e036500 RCX: ffff94c74874da00
[ 105.186460] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff94c74e036500
[ 105.186463] RBP: 0000000000000001 R08: 0000000000000002 R09: 0000000000000000
[ 105.186467] R10: ffffbb0e0387bd50 R11: 0000000000000000 R12: ffffbb0e0387bc98
[ 105.186471] R13: 0000000000000014 R14: 0000000000000000 R15: 0000000000000002
[ 105.186484] FS: 00007f166aa4d680(0000) GS:ffff94c8b7780000(0000) knlGS:0000000000000000
[ 105.186490] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 105.186494] CR2: 0000000000000000 CR3: 000000015eade001 CR4: 0000000000770ee0
[ 105.186499] PKRU: 55555554
[ 105.186502] Call Trace:
[ 105.186507] <TASK>
[ 105.186513] bpf_lwt_xmit_push_encap+0x2b/0x40
[ 105.186522] bpf_prog_a75eaad51e517912+0x41/0x49
[ 105.186536] ? kvm_clock_get_cycles+0x18/0x30
[ 105.186547] ? ktime_get+0x3c/0xa0
[ 105.186554] bpf_test_run+0x195/0x320
[ 105.186563] ? bpf_test_run+0x10f/0x320
[ 105.186579] bpf_prog_test_run_skb+0x2f5/0x4f0
[ 105.186590] __sys_bpf+0x69c/0xa40
[ 105.186603] __x64_sys_bpf+0x1e/0x30
[ 105.186611] do_syscall_64+0x59/0x110
[ 105.186620] entry_SYSCALL_64_after_hwframe+0x76/0xe0
[ 105.186649] RIP: 0033:0x7f166a97455d
Temporarily add the setting of skb->_skb_refdst before bpf_test_run to resolve the issue.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
wifi: rtlwifi: pci: fix possible use-after-free caused by unfinished irq_prepare_bcn_tasklet
The irq_prepare_bcn_tasklet is initialized in rtl_pci_init() and
scheduled when RTL_IMR_BCNINT interrupt is triggered by hardware.
But it is never killed in rtl_pci_deinit(). When the rtlwifi card
probe fails or is being detached, the ieee80211_hw is deallocated.
However, irq_prepare_bcn_tasklet may still be running or pending,
leading to use-after-free when the freed ieee80211_hw is accessed
in _rtl_pci_prepare_bcn_tasklet().
Similar to irq_tasklet, add tasklet_kill() in rtl_pci_deinit() to
ensure that irq_prepare_bcn_tasklet is properly terminated before
the ieee80211_hw is released.
The issue was identified through static analysis.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
bus: fsl-mc: use generic driver_override infrastructure
When a driver is probed through __driver_attach(), the bus' match()
callback is called without the device lock held, thus accessing the
driver_override field without a lock, which can cause a UAF.
Fix this by using the driver-core driver_override infrastructure taking
care of proper locking internally.
Note that calling match() from __driver_attach() without the device lock
held is intentional. [1]
CVSS Score
7.8
EPSS Score
0.002
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
bpf: Do not allow deleting local storage in NMI
Currently, local storage may deadlock when deferring freeing selem or
local storage through kfree_rcu(), call_rcu() or call_rcu_tasks_trace()
in NMI or reentrant. Since deleting selem in NMI is an unlikely use
case, partially mitigate it by returning error when calling from
bpf_xxx_storage_delete() helpers in NMI. Note that, it is still possible
to deadlock through reentrant. A full mitigation requires returning
error when irqs_disabled() is true, which, however is too heavy-handed
for bpf_xxx_storage_delete().
The long-term solution requires _nolock versions of call_rcu. Another
possible solution is to defer the free through irq_work [0], but it
would grow the size of selem, which is non-ideal.
The check is only needed in bpf_selem_unlink(), which is used by helpers
and syscalls. bpf_selem_unlink_nofail() is fine as it is called during
map and owner tear down that never run in NMI or reentrant.
[0] https://lore.kernel.org/bpf/20260205190233.912-1-alexei.starovoitov@gmail.com/
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix use-after-free in offloaded map/prog info fill
When querying info for an offloaded BPF map or program,
bpf_map_offload_info_fill_ns() and bpf_prog_offload_info_fill_ns()
obtain the network namespace with get_net(dev_net(offmap->netdev)).
However, the associated netdev's netns may be racing with teardown
during netns destruction. If the netns refcount has already reached 0,
get_net() performs a refcount_t increment on 0, triggering:
refcount_t: addition on 0; use-after-free.
Although rtnl_lock and bpf_devs_lock ensure the netdev pointer remains
valid, they cannot prevent the netns refcount from reaching zero.
Fix this by using maybe_get_net() instead of get_net(). maybe_get_net()
uses refcount_inc_not_zero() and returns NULL if the refcount is already
zero, which causes ns_get_path_cb() to fail and the caller to return
-ENOENT -- the correct behavior when the netns is being destroyed.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
net: pull headers in qdisc_pkt_len_segs_init()
Most ndo_start_xmit() methods expects headers of gso packets
to be already in skb->head.
net/core/tso.c users are particularly at risk, because tso_build_hdr()
does a memcpy(hdr, skb->data, hdr_len);
qdisc_pkt_len_segs_init() already does a dissection of gso packets.
Use pskb_may_pull() instead of skb_header_pointer() to make
sure drivers do not have to reimplement this.
Some malicious packets could be fed, detect them so that we can
drop them sooner with a new SKB_DROP_REASON_SKB_BAD_GSO drop_reason.
CVSS Score
8.4
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: Fix error pointer dereference
The function brcmf_chip_add_core() can return an error pointer and is
not checked. Add checks for error pointer.
Detected by Smatch:
drivers/net/wireless/broadcom/brcm80211/brcmfmac/chip.c:1010 brcmf_chip_recognition() error:
'core' dereferencing possible ERR_PTR()
drivers/net/wireless/broadcom/brcm80211/brcmfmac/chip.c:1013 brcmf_chip_recognition() error:
'core' dereferencing possible ERR_PTR()
drivers/net/wireless/broadcom/brcm80211/brcmfmac/chip.c:1016 brcmf_chip_recognition() error:
'core' dereferencing possible ERR_PTR()
drivers/net/wireless/broadcom/brcm80211/brcmfmac/chip.c:1019 brcmf_chip_recognition() error:
'core' dereferencing possible ERR_PTR()
drivers/net/wireless/broadcom/brcm80211/brcmfmac/chip.c:1022 brcmf_chip_recognition() error:
'core' dereferencing possible ERR_PTR()
[add missing wifi: prefix]
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-24