CVE-2025-37750 [High] | Use-After-Free in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix UAF in decryption with multichannel After commit f7025d861694 ("smb: client: allocate crypto only for primary server") and commit b0abcd65ec54 ("smb: client: fix UAF in async decryption"), the channels started reusing AEAD TFM from primary channel to perform synchronous decryption, but that can't done as there could be multiple cifsd threads (one per channel) simultaneously accessing it to perform decryption. This fixes the following KASAN splat when running fstest generic/249 with 'vers=3.1.1,multichannel,max_channels=4,seal' against Windows Server 2022: BUG: KASAN: slab-use-after-free in gf128mul_4k_lle+0xba/0x110 Read of size 8 at addr ffff8881046c18a0 by task cifsd/986 CPU: 3 UID: 0 PID: 986 Comm: cifsd Not tainted 6.15.0-rc1 #1 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-3.fc41 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 print_report+0x156/0x528 ? gf128mul_4k_lle+0xba/0x110 ? __virt_addr_valid+0x145/0x300 ? __phys_addr+0x46/0x90 ? gf128mul_4k_lle+0xba/0x110 kasan_report+0xdf/0x1a0 ? gf128mul_4k_lle+0xba/0x110 gf128mul_4k_lle+0xba/0x110 ghash_update+0x189/0x210 shash_ahash_update+0x295/0x370 ? __pfx_shash_ahash_update+0x10/0x10 ? __pfx_shash_ahash_update+0x10/0x10 ? __pfx_extract_iter_to_sg+0x10/0x10 ? ___kmalloc_large_node+0x10e/0x180 ? __asan_memset+0x23/0x50 crypto_ahash_update+0x3c/0xc0 gcm_hash_assoc_remain_continue+0x93/0xc0 crypt_message+0xe09/0xec0 [cifs] ? __pfx_crypt_message+0x10/0x10 [cifs] ? _raw_spin_unlock+0x23/0x40 ? __pfx_cifs_readv_from_socket+0x10/0x10 [cifs] decrypt_raw_data+0x229/0x380 [cifs] ? __pfx_decrypt_raw_data+0x10/0x10 [cifs] ? __pfx_cifs_read_iter_from_socket+0x10/0x10 [cifs] smb3_receive_transform+0x837/0xc80 [cifs] ? __pfx_smb3_receive_transform+0x10/0x10 [cifs] ? __pfx___might_resched+0x10/0x10 ? __pfx_smb3_is_transform_hdr+0x10/0x10 [cifs] cifs_demultiplex_thread+0x692/0x1570 [cifs] ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] ? rcu_is_watching+0x20/0x50 ? rcu_lockdep_current_cpu_online+0x62/0xb0 ? find_held_lock+0x32/0x90 ? kvm_sched_clock_read+0x11/0x20 ? local_clock_noinstr+0xd/0xd0 ? trace_irq_enable.constprop.0+0xa8/0xe0 ? __pfx_cifs_demultiplex_thread+0x10/0x10 [cifs] kthread+0x1fe/0x380 ? kthread+0x10f/0x380 ? __pfx_kthread+0x10/0x10 ? local_clock_noinstr+0xd/0xd0 ? ret_from_fork+0x1b/0x60 ? local_clock+0x15/0x30 ? lock_release+0x29b/0x390 ? rcu_is_watching+0x20/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x60 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK>

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-09	0.07%	0.05%	-0.02%
2	2026-02-25	0.02%	0.07%	+0.05%
3	2025-05-02	—	0.02%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-09

0.07%

0.05%

-0.02%

2026-02-25

0.02%

0.07%

+0.05%

2025-05-02

—

0.02%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.8	3.1	HIGH	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	1.8	5.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.8

3.1

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

1.8

5.9

[email protected]

OS Trackers for CVE-2025-37750

vendor	priority	summary	link
`debian`	unimportant	CVE-2025-37750 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1.	https://security-tracker.debian.org/tracker/CVE-2025-37750
`redhat`	high	—	https://access.redhat.com/security/cve/CVE-2025-37750
`suse`	medium	—	https://www.suse.com/security/cve/CVE-2025-37750/
`ubuntu`	medium	CVE-2025-37750 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, ignored 162, released 127, not-affected 115, needs-triage 2.	https://ubuntu.com/security/CVE-2025-37750

Affected software / configurations for CVE-2025-37750

Vendor	Product	Version	Raw CPE
linux	linux_kernel	>= 5.10.237, < 5.11	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 5.15.181, < 5.16	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.1.128, < 6.2	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.6.57, < 6.7	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.11.4, < 6.12.24	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.13, < 6.13.12	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	>= 6.14, < 6.14.3	cpe:2.3:o:linux:linux_kernel::::::::
linux	linux_kernel	6.15	cpe:2.3:o:linux:linux_kernel:6.15:rc1::::::

References for CVE-2025-37750

URL	Tags
https://git.kernel.org/stable/c/9502dd5c7029902f4a425bf959917a5a9e7c0e50	Patch
https://git.kernel.org/stable/c/950557922c1298464749c216d8763e97faf5d0a6	Patch
https://git.kernel.org/stable/c/aa5a1e4b882964eb79d5b5d1d1e8a1a5efbb1d15	Patch
https://git.kernel.org/stable/c/e859b216d94668bc66330e61be201234f4413d1a	Patch

URL

CVE-2025-37750 | smb: client: fix UAF in decryption with multichannel

Exploit prediction scoring system (EPSS) score for CVE-2025-37750

Common vulnerability scoring system (CVSS) metrics for CVE-2025-37750

Weakness enumeration for CVE-2025-37750

OS Trackers for CVE-2025-37750

Affected software / configurations for CVE-2025-37750

References for CVE-2025-37750