CVE-2026-53304

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.

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/1afd963fcd963db0dc5d47df6dfcf010c9c4647e
• https://git.kernel.org/stable/c/3d74e0654ac908c65a8f20373091826fe43b1363
• https://git.kernel.org/stable/c/9676ca7b1ef31a3a65b3e61e7ce3b54ce7364202
• https://git.kernel.org/stable/c/c47ccfb3d80dfed522ca06a5954ac97488d78c5a
• https://git.kernel.org/stable/c/c5f4a211e82d04ccc1809311322c47023bbe66e2
• https://git.kernel.org/stable/c/d06a310b45e153872033dd0cf19d5a2279121099
• https://git.kernel.org/stable/c/fe671d3c84ffb1b763d590c25195755adeaadaba
• https://git.kernel.org/stable/c/feade299e932967de27519338d41de348fb5b061