Kernel warning via oversized PTP virtual-clock limit
Published Oct 28, 2025 · Updated Oct 28, 2025
Improper input validation in Linux kernel 5.14 through 6.12.52 and 6.13 through 6.17.2 allows local users to trigger a kernel warning. The PTP max_vclocks_store handler accepts a value exceeding KMALLOC_MAX_SIZE divided by the integer element size and passes it to kcalloc without an upper-bound check. Reaching the path requires local write access to a PTP device's max_vclocks sysfs attribute; the public reproducer ran as UID 0 and demonstrated an allocation warning rather than data corruption.
Summary
What happened
Improper input validation in Linux kernel 5.14 through 6.12.52 and 6.13 through 6.17.2 allows local users to trigger a kernel warning. The PTP max_vclocks_store handler accepts a value exceeding KMALLOC_MAX_SIZE divided by the integer element size and passes it to kcalloc without an upper-bound check. Reaching the path requires local write access to a PTP device's max_vclocks sysfs attribute; the public reproducer ran as UID 0 and demonstrated an allocation warning rather than data corruption.
The record
- CVE
- CVE-2025-40057
- Published
- Oct 28, 2025
- Updated
- Oct 28, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- 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=5.14
- Affected versionversion=73f37068d540eba5f93ba3a0019bf479d35ebd76 <35ce5f163889dbce88eda1df661b357a09bbed87
- Affected versionversion=73f37068d540eba5f93ba3a0019bf479d35ebd76 <8dd446056336faa2283d62cefc2f576536845edc
- Affected versionversion=73f37068d540eba5f93ba3a0019bf479d35ebd76 <e9f35294e18da82162004a2f35976e7031aaf7f9
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 max_vclocks_store C reproducerfunctional · demonstrated
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Technologies
Your stack
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Your stack
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