CVE-2026-53304
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: scsi: sg: Resolve soft lockup issue when opening /dev/sgX The parameter def_reserved_size defines the default buffer size reserved for each Sg_fd and should be restricted to a range between 0 and 1,048,576 (see https://tldp.org/HOWTO/SCSI-Generic-HOWTO/proc.html). Although the function sg_proc_write_dressz enforces this limit, it is possible to bypass it by directly modifying the module parameter as shown below, which then causes a soft lockup: echo -1 > /sys/module/sg/parameters/def_reserved_size exec 4<> /dev/sg0 watchdog: BUG: soft lockup - CPU#5 stuck for 26 seconds! [bash:537] Modules loaded: CPU: 5 UID: 0 PID: 537 Command: bash, kernel version 6.19.0-rc3+ #134, PREEMPT disabled Hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS version 1.16.1-2.fc37 dated 04/01/2014 ... Call Trace: sg_build_reserve+0x5c/0xa0 sg_add_sfp+0x168/0x270 sg_open+0x16e/0x340 chrdev_open+0xbe/0x230 do_dentry_open+0x175/0x480 vfs_open+0x34/0xf0 do_open+0x265/0x3d0 path_openat+0x110/0x290 do_filp_open+0xc3/0x170 do_sys_openat2+0x71/0xe0 __x64_sys_openat+0x6d/0xa0 do_syscall_64+0x62/0x310 entry_SYSCALL_64_after_hwframe+0x76/0x7e The fix is to use module_param_cb to validate and reject invalid values assigned to def_reserved_size.
Severity
MEDIUM
CVSS score
5.5
(v3.1)
Vulnerability status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-06-26 20:17:23.637000
Last modified
2026-11-06 17:18:23.533000
View original CVE JSON
{
"id": "CVE-2026-53304",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-06-26T20:17:23.637",
"lastModified": "2026-11-06T17:18:23.533",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: sg: Resolve soft lockup issue when opening /dev/sgX\n\nThe parameter def_reserved_size defines the default buffer size reserved\nfor each Sg_fd and should be restricted to a range between 0 and 1,048,576\n(see https://tldp.org/HOWTO/SCSI-Generic-HOWTO/proc.html). Although the\nfunction sg_proc_write_dressz enforces this limit, it is possible to bypass\nit by directly modifying the module parameter as shown below, which then\ncauses a soft lockup:\n\necho -1 > /sys/module/sg/parameters/def_reserved_size\nexec 4<> /dev/sg0\n\nwatchdog: BUG: soft lockup - CPU#5 stuck for 26 seconds! [bash:537]\nModules loaded:\nCPU: 5 UID: 0 PID: 537 Command: bash, kernel version 6.19.0-rc3+ #134,\nPREEMPT disabled\nHardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS version\n1.16.1-2.fc37 dated 04/01/2014\n...\nCall Trace:\n\n sg_build_reserve+0x5c/0xa0\n sg_add_sfp+0x168/0x270\n sg_open+0x16e/0x340\n chrdev_open+0xbe/0x230\n do_dentry_open+0x175/0x480\n vfs_open+0x34/0xf0\n do_open+0x265/0x3d0\n path_openat+0x110/0x290\n do_filp_open+0xc3/0x170\n do_sys_openat2+0x71/0xe0\n __x64_sys_openat+0x6d/0xa0\n do_syscall_64+0x62/0x310\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nThe fix is to use module_param_cb to validate and reject invalid values\nassigned to def_reserved_size."
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