High 7.8Published Dec 27, 2024

CVE-2024-56631scsi: sg: Fix slab-use-after-free read in sg_release()

Updated under an hour ago (Oct 28, 2026, 7:10 AM ET)

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In the Linux kernel, the following vulnerability has been resolved: scsi: sg: Fix slab-use-after-free read in sg_release() Fix a use-after-free bug in sg_release(), detected by syzbot with KASAN: BUG: KASAN: slab-use-after-free in lock_release+0x151/0xa30 kernel/locking/lockdep.c:5838 __mutex_unlock_slowpath+0xe2/0x750 kernel/locking/mutex.c:912 sg_release+0x1f4/0x2e0 drivers/scsi/sg.c:407 In sg_release(), the function kref_put(&sfp->f_ref, sg_remove_sfp) is called before releasing the open_rel_lock mutex. The kref_put() call may decrement the reference count of sfp to zero, triggering its cleanup through sg_remove_sfp(). This cleanup includes scheduling deferred work via sg_remove_sfp_usercontext(), which ultimately frees sfp. After kref_put(), sg_release() continues to unlock open_rel_lock and may reference sfp or sdp. If sfp has already been freed, this results in a slab-use-after-free error. Move the kref_put(&sfp->f_ref, sg_remove_sfp) call after unlocking the open_rel_lock mutex. This ensures: - No references to sfp or sdp occur after the reference count is decremented. - Cleanup functions such as sg_remove_sfp() and sg_remove_sfp_usercontext() can safely execute without impacting the mutex handling in sg_release(). The fix has been tested and validated by syzbot. This patch closes the bug reported at the following syzkaller link and ensures proper sequencing of resource cleanup and mutex operations, eliminating the risk of use-after-free errors in sg_release().

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-416
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 14, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from cc833acbee9db5ca8c6162b015b4c93863c6f821 before e19acb1926c4a1f30ee1ec84d8afba2d975bd534; from cc833acbee9db5ca8c6162b015b4c93863c6f821 before 285ce1f89f8d414e7eecab5ef5118cd512596318; from cc833acbee9db5ca8c6162b015b4c93863c6f821 before 198b89dd5a595ee3f96e5ce5c448b0484cd0e53c; from cc833acbee9db5ca8c6162b015b4c93863c6f821 before 275b8347e21ab8193e93223a8394a806e4ba8918; from cc833acbee9db5ca8c6162b015b4c93863c6f821 before 59b30afa578637169e2819536bb66459fdddc39d; from cc833acbee9db5ca8c6162b015b4c93863c6f821 before 1f5e2f1ca5875728fcf62bc1a054707444ab4960; from cc833acbee9db5ca8c6162b015b4c93863c6f821 before f10593ad9bc36921f623361c9e3dd96bd52d85ee; 3a27c0defb0315760100f8b1adc7c4acbe04c884; and 1 more ranges	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	before V1.1.1	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 3.16.85 before 6.6.66; from 6.7 before 6.12.5; 6.13	NVD

References

References

https://git.kernel.org/stable/c/e19acb1926c4a1f30ee1ec84d8afba2d975bd534
https://git.kernel.org/stable/c/285ce1f89f8d414e7eecab5ef5118cd512596318
https://git.kernel.org/stable/c/198b89dd5a595ee3f96e5ce5c448b0484cd0e53c
https://git.kernel.org/stable/c/275b8347e21ab8193e93223a8394a806e4ba8918
https://git.kernel.org/stable/c/59b30afa578637169e2819536bb66459fdddc39d	patch
https://git.kernel.org/stable/c/1f5e2f1ca5875728fcf62bc1a054707444ab4960	patch
https://git.kernel.org/stable/c/f10593ad9bc36921f623361c9e3dd96bd52d85ee	patch
https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
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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.