CVE-2025-40255
In the Linux kernel, the following vulnerability has been resolved: net: core: prevent NULL deref in generic_hwtstamp_ioctl_lower() The ethtool tsconfig Netlink path can trigger a null pointer dereference. A call chain such as: tsconfig_prepare_data() -> dev_get_hwtstamp_phylib() -> vlan_hwtstamp_get() -> generic_hwtstamp_get_lower() -> generic_hwtstamp_ioctl_lower() results in generic_hwtstamp_ioctl_lower() being called with kernel_cfg->ifr as NULL. The generic_hwtstamp_ioctl_lower() function does not expect a NULL ifr and dereferences it, leading to a system crash. Fix this by adding a NULL check for kernel_cfg->ifr in generic_hwtstamp_ioctl_lower(). If ifr is NULL, return -EINVAL.
Affected versions
Linux kernel versions
6.14
and later are affected. Fixed in
6.17.10,
6.18
and their respective stable series.
References
The following references provide additional information about CVE-2025-40255 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/8817f816ae41908e9625c0770c4af0dcdcc01238
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PatchKernel patch commithttps://git.kernel.org/stable/c/f796a8dec9beafcc0f6f0d3478ed685a15c5e062
Frequently asked questions
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What is CVE-2025-40255?
CVE-2025-40255 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.14 onward and has been patched in 6.17.10 and 6.18. CVE-2025-40255 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2025-40255?
Yes — CVE-2025-40255 has been patched. Fixed versions include 6.17.10 and 6.18. If you are running Linux kernel 6.14 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2025-40255 actively exploited?
No — CVE-2025-40255 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.