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.
Conclusion & alert: CVE-2025-40255 is rated Low Risk (5.2/100): low exploitation likelihood (EPSS 0.15%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.02% | 0.15% | +0.14% |
| 2 | 2025-12-05 | — | 0.02% | — |
Full EPSS history (2 records total)
CVSS metrics for this CVE.
No CVSS data in dataset for this CVE.
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2025-40255 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2025-40255 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2025-40255 |
suse
|
medium | CVE-2025-40255 severity moderate: SUSE including 344 source package names (13.2-9.1:libsystemd0-254.23-1.1, 13.2-9.1:libudev1-254.23-1.1, …), 709 product×package rows across 82 product lines (Container suse/sl-micro/6.0/baremetal-os-container, Container suse/sl-micro/6.0/base-os-container, … (82 product lines)): Fixed 258, Known Affected 231, Known Not Affected 195, First Fixed 25. | https://www.suse.com/security/cve/CVE-2025-40255/ |
ubuntu
|
medium | CVE-2025-40255 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1405 status rows across 9 suites (bionic, focal, jammy, noble, plucky, questing, trusty, upstream, xenial): DNE 1010, ignored 178, not-affected 112, released 100, needed 5. | https://ubuntu.com/security/CVE-2025-40255 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| No affected products in dataset. | |||