CVE-2025-39887
Published: September 24, 2025Last modified: September 24, 2025
Description
In the Linux kernel, the following vulnerability has been resolved: tracing/osnoise: Fix null-ptr-deref in bitmap_parselist() A crash was observed with the following output: BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 92 Comm: osnoise_cpus Not tainted 6.17.0-rc4-00201-gd69eb204c255 #138 PREEMPT(voluntary) RIP: 0010:bitmap_parselist+0x53/0x3e0 Call Trace: <TASK> osnoise_cpus_write+0x7a/0x190 vfs_write+0xf8/0x410 ? do_sys_openat2+0x88/0xd0 ksys_write+0x60/0xd0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> This issue can be reproduced by below code: fd=open("/sys/kernel/debug/tracing/osnoise/cpus", O_WRONLY); write(fd, "0-2", 0); When user pass 'count=0' to osnoise_cpus_write(), kmalloc() will return ZERO_SIZE_PTR (16) and cpulist_parse() treat it as a normal value, which trigger the null pointer dereference. Add check for the parameter 'count'.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 5.5 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Not affected (6.1.33-r0) |
| 25 LTS | linux-lts | Not affected (6.6.89-r0) | |
| Stream | linux-lts | Not affected (6.1.33-r0) |