UBUNTU-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.
02 / AFFECTED SOFTWARE
Affected packages
8 explicit affected versions
11 explicit affected versions
4 explicit affected versions
17 explicit affected versions
2 explicit affected versions
53 explicit affected versions
116 explicit affected versions
87 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
10 explicit affected versions
6 explicit affected versions
97 explicit affected versions
59 explicit affected versions
24 explicit affected versions
2 explicit affected versions
82 explicit affected versions
83 explicit affected versions
91 explicit affected versions
84 explicit affected versions
76 explicit affected versions
10 explicit affected versions
85 explicit affected versions
7 explicit affected versions
37 explicit affected versions
26 explicit affected versions
89 explicit affected versions
191 explicit affected versions
12 explicit affected versions
44 explicit affected versions
7 explicit affected versions
84 explicit affected versions
40 explicit affected versions
13 explicit affected versions
11 explicit affected versions
35 explicit affected versions
1 explicit affected versions
49 explicit affected versions
47 explicit affected versions
62 explicit affected versions
18 explicit affected versions
40 explicit affected versions
118 explicit affected versions
1 explicit affected versions
45 explicit affected versions
120 explicit affected versions
13 explicit affected versions
4 explicit affected versions
121 explicit affected versions
111 explicit affected versions
23 explicit affected versions
52 explicit affected versions
124 explicit affected versions
1 explicit affected versions
1 explicit affected versions
21 explicit affected versions
48 explicit affected versions
7 explicit affected versions
16 explicit affected versions
10 explicit affected versions
20 explicit affected versions
76 explicit affected versions
7 explicit affected versions
10 explicit affected versions
7 explicit affected versions
12 explicit affected versions
14 explicit affected versions
10 explicit affected versions
1 explicit affected versions
7 explicit affected versions
17 explicit affected versions
104 explicit affected versions
12 explicit affected versions
105 explicit affected versions
12 explicit affected versions
41 explicit affected versions
9 explicit affected versions
9 explicit affected versions
120 explicit affected versions
43 explicit affected versions
16 explicit affected versions
95 explicit affected versions
6 explicit affected versions
17 explicit affected versions
27 explicit affected versions
34 explicit affected versions
154 explicit affected versions
10 explicit affected versions
37 explicit affected versions
10 explicit affected versions
11 explicit affected versions
13 explicit affected versions
10 explicit affected versions
39 explicit affected versions
3 explicit affected versions
10 explicit affected versions
11 explicit affected versions
65 explicit affected versions
1 explicit affected versions
26 explicit affected versions
10 explicit affected versions
13 explicit affected versions
144 explicit affected versions
34 explicit affected versions
1 explicit affected versions
29 explicit affected versions
111 explicit affected versions
13 explicit affected versions
12 explicit affected versions
41 explicit affected versions
40 explicit affected versions
8 explicit affected versions
1 explicit affected versions
100 explicit affected versions
89 explicit affected versions
52 explicit affected versions
33 explicit affected versions
23 explicit affected versions
58 explicit affected versions
10 explicit affected versions
20 explicit affected versions
188 explicit affected versions
19 explicit affected versions
11 explicit affected versions
5 explicit affected versions
12 explicit affected versions
11 explicit affected versions
7 explicit affected versions
12 explicit affected versions
10 explicit affected versions
16 explicit affected versions
138 explicit affected versions
5 explicit affected versions
74 explicit affected versions
132 explicit affected versions
90 explicit affected versions
165 explicit affected versions
26 explicit affected versions
39 explicit affected versions
1 explicit affected versions
66 explicit affected versions
46 explicit affected versions
35 explicit affected versions
48 explicit affected versions
11 explicit affected versions
10 explicit affected versions
13 explicit affected versions
139 explicit affected versions
78 explicit affected versions
16 explicit affected versions
88 explicit affected versions
50 explicit affected versions
10 explicit affected versions
116 explicit affected versions
3 explicit affected versions
132 explicit affected versions
1 explicit affected versions
51 explicit affected versions
93 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
15 explicit affected versions
16 explicit affected versions
92 explicit affected versions
18 explicit affected versions
43 explicit affected versions
1 explicit affected versions
12 explicit affected versions
70 explicit affected versions
77 explicit affected versions
7 explicit affected versions
8 explicit affected versions
27 explicit affected versions
3 explicit affected versions
63 explicit affected versions
121 explicit affected versions
98 explicit affected versions
43 explicit affected versions
8 explicit affected versions
54 explicit affected versions
3 explicit affected versions
5 explicit affected versions
8 explicit affected versions
6 explicit affected versions
1 explicit affected versions
10 explicit affected versions
7 explicit affected versions
46 explicit affected versions
13 explicit affected versions
110 explicit affected versions
13 explicit affected versions
72 explicit affected versions
7 explicit affected versions
140 explicit affected versions
8 explicit affected versions
94 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
36 explicit affected versions
108 explicit affected versions
11 explicit affected versions
80 explicit affected versions
56 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
7 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
50 explicit affected versions
14 explicit affected versions
38 explicit affected versions
167 explicit affected versions
9 explicit affected versions
17 explicit affected versions
39 explicit affected versions
18 explicit affected versions
14 explicit affected versions
90 explicit affected versions
6 explicit affected versions
97 explicit affected versions
121 explicit affected versions
4 explicit affected versions
79 explicit affected versions
8 explicit affected versions
10 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
88 explicit affected versions
78 explicit affected versions
78 explicit affected versions
7 explicit affected versions
13 explicit affected versions
43 explicit affected versions
77 explicit affected versions
16 explicit affected versions
119 explicit affected versions
10 explicit affected versions
45 explicit affected versions
88 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
14 explicit affected versions
11 explicit affected versions
1 explicit affected versions
69 explicit affected versions
123 explicit affected versions
19 explicit affected versions
6 explicit affected versions
39 explicit affected versions
77 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/d06a310b45e153872033dd0cf19d5a2279121099
- 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
- https://ubuntu.com/security/CVE-2026-53304
- https://ubuntu.com/security/notices/USN-8566-1
- https://ubuntu.com/security/notices/USN-8567-1
- https://ubuntu.com/security/notices/USN-8568-1
- https://ubuntu.com/security/notices/USN-8569-1
- https://ubuntu.com/security/notices/USN-8574-1
- https://ubuntu.com/security/notices/USN-8574-2
- https://ubuntu.com/security/notices/USN-8574-3
- https://ubuntu.com/security/notices/USN-8575-1
- https://ubuntu.com/security/notices/USN-8575-2
- https://ubuntu.com/security/notices/USN-8575-3
- https://ubuntu.com/security/notices/USN-8576-1
- https://ubuntu.com/security/notices/USN-8576-2
- https://ubuntu.com/security/notices/USN-8593-1
- https://ubuntu.com/security/notices/USN-8595-1
- https://ubuntu.com/security/notices/USN-8595-2
- https://ubuntu.com/security/notices/USN-8595-3
- https://ubuntu.com/security/notices/USN-8596-1
- https://ubuntu.com/security/notices/USN-8603-1
- https://ubuntu.com/security/notices/USN-8606-1
- https://ubuntu.com/security/notices/USN-8607-1
- https://ubuntu.com/security/notices/USN-8608-1
- https://ubuntu.com/security/notices/USN-8609-1
- https://ubuntu.com/security/notices/USN-8610-1
- https://ubuntu.com/security/notices/USN-8618-1
- https://ubuntu.com/security/notices/USN-8619-1
- https://ubuntu.com/security/notices/USN-8620-1
- https://ubuntu.com/security/notices/USN-8620-2
- https://ubuntu.com/security/notices/USN-8620-3
- https://ubuntu.com/security/notices/USN-8620-4
- https://www.cve.org/CVERecord?id=CVE-2026-53304