Linux Kernel up to 6.16.7/6.17-rc5 bitmap_parselist null pointer dereference

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.16.7/6.17-rc5. Affected by this vulnerability is the function bitmap_parselist. Performing a manipulation results in null pointer dereference. This vulnerability is identified as CVE-2025-39887. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.16.7/6.17-rc5. This affects the function bitmap_parselist. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

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'.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-39887 since 04/16/2025. The exploitability is told to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 265883 (Linux Distros Unpatched Vulnerability : CVE-2025-39887), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.16.8 or 6.17-rc6 eliminates this vulnerability. Applying the patch e33228a2cc7ff706ca88533464e8a3b525b961ed/c1628c00c4351dd0727ef7f670694f68d9e663d8 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (265883) and CERT Bund (WID-SEC-2025-2107). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• RESF Rocky Linux
• Dell Secure Connect Gateway
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.16.0
• 6.16.1
• 6.16.2
• 6.16.3
• 6.16.4
• 6.16.5
• 6.16.6
• 6.16.7
• 6.17-rc1
• 6.17-rc2
• 6.17-rc3
• 6.17-rc4
• 6.17-rc5

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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Entryinfo

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