Local kernel crash via zero refcount increment
Published Feb 14, 2026 · Updated Feb 14, 2026
Denial of service in Linux Kernel 6.18 through 6.18.7 allows local users to crash the kernel via crafted perf event mappings. In perf_mmap_rb(), a group member that copied output_event retains event->rb while event->mmap_count is zero, so refcount_inc() increments a zero refcount and reaches a use-after-free warning. A local low-privileged user must map a leader, create a PERF_FLAG_FD_OUTPUT member, and map that member; the reported consequence is service interruption rather than data access or modification.
Summary
What happened
Denial of service in Linux Kernel 6.18 through 6.18.7 allows local users to crash the kernel via crafted perf event mappings. In perf_mmap_rb(), a group member that copied output_event retains event->rb while event->mmap_count is zero, so refcount_inc() increments a zero refcount and reaches a use-after-free warning. A local low-privileged user must map a leader, create a PERF_FLAG_FD_OUTPUT member, and map that member; the reported consequence is service interruption rather than data access or modification.
The record
- CVE
- CVE-2026-23127
- Published
- Feb 14, 2026
- Updated
- Feb 14, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 14, 2026CVE publishedPublication date reported by the CVE source.
- Feb 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=448f97fba9013ffa13f5dd82febd18836b189499 <23c0e4bd93d0b250775162faf456470485ac9fc7
- Affected versionversion=448f97fba9013ffa13f5dd82febd18836b189499 <d06bf78e55d5159c1b00072e606ab924ffbbad35
- Affected versionversion=6.18
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- Linux perf mmap refcount warning PoCproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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