Local privilege escalation via stale wait-queue entry
Published Oct 28, 2025 · Updated Oct 28, 2025
Use-after-free in the io_uring waitid implementation in Linux allows local users to gain kernel privileges or crash the host. io_waitid_wait() returned success without removing its wait-queue entry during cancellation, allowing a competing callback to dereference reclaimed io_waitid_async memory. An unprivileged local user can create an io_uring ring and coordinate child signals with cancellation to obtain kernel-memory read, write, or control-flow primitives, or trigger a kernel panic.
Summary
What happened
Use-after-free in the io_uring waitid implementation in Linux allows local users to gain kernel privileges or crash the host. io_waitid_wait() returned success without removing its wait-queue entry during cancellation, allowing a competing callback to dereference reclaimed io_waitid_async memory. An unprivileged local user can create an io_uring ring and coordinate child signals with cancellation to obtain kernel-memory read, write, or control-flow primitives, or trigger a kernel panic.
The record
- CVE
- CVE-2025-40047
- Published
- Oct 28, 2025
- Updated
- Oct 28, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-662, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 28, 2025CVE publishedPublication date reported by the CVE source.
- Oct 28, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.7
- Affected versionversion=f31ecf671ddc498f20219453395794ff2383e06b <2f8229d53d984c6a05b71ac9e9583d4354e3b91f
- Affected versionversion=f31ecf671ddc498f20219453395794ff2383e06b <3e2205db2f0608898d535da1964e1b376aacfdaa
- Affected versionversion=f31ecf671ddc498f20219453395794ff2383e06b <696ba6032081e617564a8113a001b8d7943cb928
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- syzbot IORING_OP_WAITID race reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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