CVE-2026-90100

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ptp: netc: fix period truncation and potential divide-by-zero in PEROUT

The max_period bound in net_timer_enable_perout() was computed as:

max_period = (u64)NETC_TMR_DEFAULT_FIPER + integral_period;

which exceeds U32_MAX when integral_period > 0 (e.g. 0x100000002 for

the default 333333333 Hz clock). A period_ns that passes this check but

exceeds U32_MAX is then silently truncated when stored into the u32

struct netc_pp::period field.

A truncated value of zero can reach netc_timer_set_perout_alarm(), where

the local u32 period variable would also be 0, causing a divide-by-zero

in roundup_u64(delta, period) whenever the stime < min_time branch is

taken (which always happens for a start time of {0, 0}).

Additionally, netc_timer_enable_periodic_pulse() and

netc_timer_enable_fiper() both compute:

fiper = pp->period - integral_period;

A zero pp->period results in an unsigned wraparound to 0xFFFFFFFD,

mis-programm

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References