Linux: >> Linux Kernel >> 5.15.204 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_tcm: Fix NULL pointer dereferences in nexus handling
The `tpg->tpg_nexus` pointer in the USB Target driver is dynamically
managed and tied to userspace configuration via ConfigFS. It can be
NULL if the USB host sends requests before the nexus is fully
established or immediately after it is dropped.
Currently, functions like `bot_submit_command()` and the data
transfer paths retrieve `tv_nexus = tpg->tpg_nexus` and immediately
dereference `tv_nexus->tvn_se_sess` without any validation. If a
malicious or misconfigured USB host sends a BOT (Bulk-Only Transport)
command during this race window, it triggers a NULL pointer
dereference, leading to a kernel panic (local DoS).
This exposes an inconsistent API usage within the module, as peer
functions like `usbg_submit_command()` and `bot_send_bad_response()`
correctly implement a NULL check for `tv_nexus` before proceeding.
Fix this by bringing consistency to the nexus handling. Add the
missing `if (!tv_nexus)` checks to the vulnerable BOT command and
request processing paths, aborting the command gracefully with an
error instead of crashing the system.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
scsi: hisi_sas: Fix NULL pointer exception during user_scan()
user_scan() invokes updated sas_user_scan() for channel 0, and if
successful, iteratively scans remaining channels (1 to shost->max_channel)
via scsi_scan_host_selected() in commit 37c4e72b0651 ("scsi: Fix
sas_user_scan() to handle wildcard and multi-channel scans"). However,
hisi_sas supports only one channel, and the current value of max_channel is
1. sas_user_scan() for channel 1 will trigger the following NULL pointer
exception:
[ 441.554662] Unable to handle kernel NULL pointer dereference at virtual address 00000000000008b0
[ 441.554699] Mem abort info:
[ 441.554710] ESR = 0x0000000096000004
[ 441.554718] EC = 0x25: DABT (current EL), IL = 32 bits
[ 441.554723] SET = 0, FnV = 0
[ 441.554726] EA = 0, S1PTW = 0
[ 441.554730] FSC = 0x04: level 0 translation fault
[ 441.554735] Data abort info:
[ 441.554737] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[ 441.554742] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[ 441.554747] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[ 441.554752] user pgtable: 4k pages, 48-bit VAs, pgdp=00000828377a6000
[ 441.554757] [00000000000008b0] pgd=0000000000000000, p4d=0000000000000000
[ 441.554769] Internal error: Oops: 0000000096000004 [#1] SMP
[ 441.629589] Modules linked in: arm_spe_pmu arm_smmuv3_pmu tpm_tis_spi hisi_uncore_sllc_pmu hisi_uncore_pa_pmu hisi_uncore_l3c_pmu hisi_uncore_hha_pmu hisi_uncore_ddrc_pmu hisi_uncore_cpa_pmu hns3_pmu hisi_ptt hisi_pcie_pmu tpm_tis_core spidev spi_hisi_sfc_v3xx hisi_uncore_pmu spi_dw_mmio fuse hclge hclge_common hisi_sec2 hisi_hpre hisi_zip hisi_qm hns3 hisi_sas_v3_hw sm3_ce sbsa_gwdt hnae3 hisi_sas_main uacce hisi_dma i2c_hisi dm_mirror dm_region_hash dm_log dm_mod
[ 441.670819] CPU: 46 UID: 0 PID: 6994 Comm: bash Kdump: loaded Not tainted 7.0.0-rc2+ #84 PREEMPT
[ 441.691327] pstate: 81400009 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[ 441.698277] pc : sas_find_dev_by_rphy+0x44/0x118
[ 441.702896] lr : sas_find_dev_by_rphy+0x3c/0x118
[ 441.707502] sp : ffff80009abbba40
[ 441.710805] x29: ffff80009abbba40 x28: ffff082819a40008 x27: ffff082810c37c08
[ 441.717930] x26: ffff082810c37c28 x25: ffff082819a40290 x24: ffff082810c37c00
[ 441.725054] x23: 0000000000000000 x22: 0000000000000001 x21: ffff082819a40000
[ 441.732179] x20: ffff082819a40290 x19: 0000000000000000 x18: 0000000000000020
[ 441.739304] x17: 0000000000000000 x16: ffffb5dad6bda690 x15: 00000000ffffffff
[ 441.746428] x14: ffff082814c3b26c x13: 00000000ffffffff x12: ffff082814c3b26a
[ 441.753553] x11: 00000000000000c0 x10: 000000000000003a x9 : ffffb5dad5ea94f4
[ 441.760678] x8 : 000000000000003a x7 : ffff80009abbbab0 x6 : 0000000000000030
[ 441.767802] x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
[ 441.774926] x2 : ffff08280f35a300 x1 : ffffb5dad7127180 x0 : 0000000000000000
[ 441.782053] Call trace:
[ 441.784488] sas_find_dev_by_rphy+0x44/0x118 (P)
[ 441.789095] sas_target_alloc+0x24/0xb0
[ 441.792920] scsi_alloc_target+0x290/0x330
[ 441.797010] __scsi_scan_target+0x88/0x258
[ 441.801096] scsi_scan_channel+0x74/0xb8
[ 441.805008] scsi_scan_host_selected+0x170/0x188
[ 441.809615] sas_user_scan+0xfc/0x148
[ 441.813267] store_scan+0x10c/0x180
[ 441.816743] dev_attr_store+0x20/0x40
[ 441.820398] sysfs_kf_write+0x84/0xa8
[ 441.824054] kernfs_fop_write_iter+0x130/0x1c8
[ 441.828487] vfs_write+0x2c0/0x370
[ 441.831880] ksys_write+0x74/0x118
[ 441.835271] __arm64_sys_write+0x24/0x38
[ 441.839182] invoke_syscall+0x50/0x120
[ 441.842919] el0_svc_common.constprop.0+0xc8/0xf0
[ 441.847611] do_el0_svc+0x24/0x38
[ 441.850913] el0_svc+0x38/0x158
[ 441.854043] el0t_64_sync_handler+0xa0/0xe8
[ 441.858214] el0t_64_sync+0x1ac/0x1b0
[ 441.861865] Code: aa1303e0 97ff70a8 34ffff80 d10a4273 (f9445a75)
[ 441.867946] ---[ end trace 0000000000000000 ]---
Therefore
---truncated---
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
powerpc, perf: Check that current->mm is alive before getting user callchain
It may happen that mm is already released, which leads to kernel panic.
This adds the NULL check for current->mm, similarly to
commit 20afc60f892d ("x86, perf: Check that current->mm is alive before getting user callchain").
I was getting this panic when running a profiling BPF program
(profile.py from bcc-tools):
[26215.051935] Kernel attempted to read user page (588) - exploit attempt? (uid: 0)
[26215.051950] BUG: Kernel NULL pointer dereference on read at 0x00000588
[26215.051952] Faulting instruction address: 0xc00000000020fac0
[26215.051957] Oops: Kernel access of bad area, sig: 11 [#1]
[...]
[26215.052049] Call Trace:
[26215.052050] [c000000061da6d30] [c00000000020fc10] perf_callchain_user_64+0x2d0/0x490 (unreliable)
[26215.052054] [c000000061da6dc0] [c00000000020f92c] perf_callchain_user+0x1c/0x30
[26215.052057] [c000000061da6de0] [c0000000005ab2a0] get_perf_callchain+0x100/0x360
[26215.052063] [c000000061da6e70] [c000000000573bc8] bpf_get_stackid+0x88/0xf0
[26215.052067] [c000000061da6ea0] [c008000000042258] bpf_prog_16d4ab9ab662f669_do_perf_event+0xf8/0x274
[...]
In addition, move storing the top-level stack entry to generic
perf_callchain_user to make sure the top-evel entry is always captured,
even if current->mm is NULL.
[Maddy: fixed message to avoid checkpatch format style error]
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
ceph: fix memory leaks in ceph_mdsc_build_path()
Add __putname() calls to error code paths that did not free the "path"
pointer obtained by __getname(). If ownership of this pointer is not
passed to the caller via path_info.path, the function must free it
before returning.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
kprobes: avoid crash when rmmod/insmod after ftrace killed
After we hit ftrace is killed by some errors, the kernel crash if
we remove modules in which kprobe probes.
BUG: unable to handle page fault for address: fffffbfff805000d
PGD 817fcc067 P4D 817fcc067 PUD 817fc8067 PMD 101555067 PTE 0
Oops: Oops: 0000 [#1] SMP KASAN PTI
CPU: 4 UID: 0 PID: 2012 Comm: rmmod Tainted: G W OE
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
RIP: 0010:kprobes_module_callback+0x89/0x790
RSP: 0018:ffff88812e157d30 EFLAGS: 00010a02
RAX: 1ffffffff805000d RBX: dffffc0000000000 RCX: ffffffff86a8de90
RDX: ffffed1025c2af9b RSI: 0000000000000008 RDI: ffffffffc0280068
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1025c2af9a
R10: ffff88812e157cd7 R11: 205d323130325420 R12: 0000000000000002
R13: ffffffffc0290488 R14: 0000000000000002 R15: ffffffffc0280040
FS: 00007fbc450dd740(0000) GS:ffff888420331000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbfff805000d CR3: 000000010f624000 CR4: 00000000000006f0
Call Trace:
<TASK>
notifier_call_chain+0xc6/0x280
blocking_notifier_call_chain+0x60/0x90
__do_sys_delete_module.constprop.0+0x32a/0x4e0
do_syscall_64+0x5d/0xfa0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
This is because the kprobe on ftrace does not correctly handles
the kprobe_ftrace_disabled flag set by ftrace_kill().
To prevent this error, check kprobe_ftrace_disabled in
__disarm_kprobe_ftrace() and skip all ftrace related operations.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
net/tcp-md5: Fix MAC comparison to be constant-time
To prevent timing attacks, MACs need to be compared in constant
time. Use the appropriate helper function for this.
CVSS Score
9.4
EPSS Score
0.004
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: Don't log keys in SMB3 signing and encryption key generation
When KSMBD_DEBUG_AUTH logging is enabled, generate_smb3signingkey() and
generate_smb3encryptionkey() log the session, signing, encryption, and
decryption key bytes. Remove the logs to avoid exposing credentials.
CVSS Score
8.1
EPSS Score
0.002
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
smb: server: fix use-after-free in smb2_open()
The opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is
dereferenced after rcu_read_unlock(), creating a use-after-free
window.
CVSS Score
9.8
EPSS Score
0.003
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix in-place encryption corruption in SMB2_write()
SMB2_write() places write payload in iov[1..n] as part of rq_iov.
smb3_init_transform_rq() pointer-shares rq_iov, so crypt_message()
encrypts iov[1] in-place, replacing the original plaintext with
ciphertext. On a replayable error, the retry sends the same iov[1]
which now contains ciphertext instead of the original data,
resulting in corruption.
The corruption is most likely to be observed when connections are
unstable, as reconnects trigger write retries that re-send the
already-encrypted data.
This affects SFU mknod, MF symlinks, etc. On kernels before
6.10 (prior to the netfs conversion), sync writes also used
this path and were similarly affected. The async write path
wasn't unaffected as it uses rq_iter which gets deep-copied.
Fix by moving the write payload into rq_iter via iov_iter_kvec(),
so smb3_init_transform_rq() deep-copies it before encryption.
CVSS Score
8.1
EPSS Score
0.002
Published
2026-05-08
In the Linux kernel, the following vulnerability has been resolved:
i3c: mipi-i3c-hci: Fix race in DMA ring dequeue
The HCI DMA dequeue path (hci_dma_dequeue_xfer()) may be invoked for
multiple transfers that timeout around the same time. However, the
function is not serialized and can race with itself.
When a timeout occurs, hci_dma_dequeue_xfer() stops the ring, processes
incomplete transfers, and then restarts the ring. If another timeout
triggers a parallel call into the same function, the two instances may
interfere with each other - stopping or restarting the ring at unexpected
times.
Add a mutex so that hci_dma_dequeue_xfer() is serialized with respect to
itself.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-08