Critical 9.8Published May 1, 2025

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

Updated under an hour ago (2026-10-22 01:50 UTC)

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Exploited in the last 30 days

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>

CVSS: 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 21, 2026
First seen by InfoSec Signals: Oct 21, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from c8c6af46286a513769650935ff858fc67cf51a6d before 08160de2a65227e5b64fcb6765cd936ec384ee93; from b0abcd65ec545701b8793e12bc27dc98042b151a before aa5a1e4b882964eb79d5b5d1d1e8a1a5efbb1d15; from b0abcd65ec545701b8793e12bc27dc98042b151a before e859b216d94668bc66330e61be201234f4413d1a; from b0abcd65ec545701b8793e12bc27dc98042b151a before 950557922c1298464749c216d8763e97faf5d0a6; from b0abcd65ec545701b8793e12bc27dc98042b151a before 9502dd5c7029902f4a425bf959917a5a9e7c0e50; 8f14a476abba13144df5434871a7225fd29af633; ef51c0d544b1518b35364480317ab6d3468f205d; bce966530fd5542bbb422cb45ecb775f7a1a6bc3; and 6 more ranges	CNA record
linux linux_kernel linux:linux_kernel	from 5.10.237 before 5.11; from 5.15.181 before 5.16; from 6.1.128 before 6.2; from 6.6.57 before 6.7; from 6.11.4 before 6.12.24; from 6.13 before 6.13.12; from 6.14 before 6.14.3; 6.15	NVD

References

https://git.kernel.org/stable/c/08160de2a65227e5b64fcb6765cd936ec384ee93
https://git.kernel.org/stable/c/aa5a1e4b882964eb79d5b5d1d1e8a1a5efbb1d15patch
https://git.kernel.org/stable/c/e859b216d94668bc66330e61be201234f4413d1apatch
https://git.kernel.org/stable/c/950557922c1298464749c216d8763e97faf5d0a6patch
https://git.kernel.org/stable/c/9502dd5c7029902f4a425bf959917a5a9e7c0e50patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.