CVE-2025-39887

tracing/osnoise: Fix null-ptr-deref in bitmap_parselist()

MEDIUM
5.5
CVSS Score
Published: September 23, 2025 at 06:00 AM UTC
Updated: October 19, 2026 at 09:10 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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'.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.16 ≤ v < 6.16.817f89102fe23d7389085a8820550df688f79888a6.166.176.17 rc16.17 rc26.17 rc36.17 rc46.17 rc5
Vendor states this is fixed in c1628c00c4351dd0727ef7f670694f68d9e663d8 (fixed)
Vendor states this is fixed in e33228a2cc7ff706ca88533464e8a3b525b961ed (fixed)
Vendor states this is fixed in 6.16 (unaffected)
Vendor states this is fixed in 6.16.8 (unaffected)
Vendor states this is fixed in 6.17 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.5MEDIUMCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-476

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