CVE-2025-38443
nbd: fix uaf in nbd_genl_connect() error path
In the Linux kernel, the following vulnerability has been resolved: nbd: fix uaf in nbd_genl_connect() error path There is a use-after-free issue in nbd: block nbd6: Receive control failed (result -104) block nbd6: shutting down sockets ================================================================== BUG: KASAN: slab-use-after-free in recv_work+0x694/0xa80 drivers/block/nbd.c:1022 Write of size 4 at addr ffff8880295de478 by task kworker/u33:0/67 CPU: 2 UID: 0 PID: 67 Comm: kworker/u33:0 Not tainted 6.15.0-rc5-syzkaller-00123-g2c89c1b655c0 #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Workqueue: nbd6-recv recv_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_dec include/linux/atomic/atomic-instrumented.h:592 [inline] recv_work+0x694/0xa80 drivers/block/nbd.c:1022 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> nbd_genl_connect() does not properly stop the device on certain error paths after nbd_start_device() has been called. This causes the error path to put nbd->config while recv_work continue to use the config after putting it, leading to use-after-free in recv_work. This patch moves nbd_start_device() after the backend file creation.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| Linux Linux |
≥ 6497ef8df568afbf5f3e38825a4590ff41611a54; < cb121c47f364b51776c4db904a6a5a90ab0a7ec5 (affected, git) ≥ 6497ef8df568afbf5f3e38825a4590ff41611a54; < 91fa560c73a8126868848ed6cd70607cbf8d87e2 (affected, git) ≥ 6497ef8df568afbf5f3e38825a4590ff41611a54; < d46186eb7bbd9a11c145120f2d77effa8d4d44c2 (affected, git) ≥ 6497ef8df568afbf5f3e38825a4590ff41611a54; < 8586552df591e0a367eff44af0c586213eeecc3f (affected, git) ≥ 6497ef8df568afbf5f3e38825a4590ff41611a54; < 002aca89753f666d878ca0eb8584c372684ac4ba (affected, git) ≥ 6497ef8df568afbf5f3e38825a4590ff41611a54; < aa9552438ebf015fc5f9f890dbfe39f0c53cf37e (affected, git) Other versions: unaffected |
CNA: Linux |
| Linux Linux |
5.14 (affected) ≥ 0; < 5.14 (unaffected, semver) ≥ 5.15.189; ≤ 5.15.* (unaffected, semver) ≥ 6.1.146; ≤ 6.1.* (unaffected, semver) ≥ 6.6.99; ≤ 6.6.* (unaffected, semver) ≥ 6.12.39; ≤ 6.12.* (unaffected, semver) ≥ 6.15.7; ≤ 6.15.* (unaffected, semver) ≥ 6.16; ≤ * (unaffected, original_commit_for_fix) Other versions: affected |
CNA: Linux |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
No CVSS assessment reported. An unscored record is not a low-severity determination.
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://git.kernel.org/stable/c/cb121c47f364b51776c4db904a6a5a90ab0a7ec5CNA: Linux
- https://git.kernel.org/stable/c/91fa560c73a8126868848ed6cd70607cbf8d87e2CNA: Linux
- https://git.kernel.org/stable/c/d46186eb7bbd9a11c145120f2d77effa8d4d44c2CNA: Linux
- https://git.kernel.org/stable/c/8586552df591e0a367eff44af0c586213eeecc3fCNA: Linux
- https://git.kernel.org/stable/c/002aca89753f666d878ca0eb8584c372684ac4baCNA: Linux
- https://git.kernel.org/stable/c/aa9552438ebf015fc5f9f890dbfe39f0c53cf37eCNA: Linux
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlADP: CVE
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