net/ipv6: ioam6: prevent schema length wraparound in trace fill

In the Linux kernel, the following vulnerability has been resolved: net/ipv6: ioam6: prevent schema length wraparound in trace fill ioam6_fill_trace_data() stores the schema contribution to the trace length in a u8. With bit 22 enabled and the largest schema payload, sclen becomes 1 + 1020 / 4, wraps from 256 to 0, and bypasses the remaining-space check. __ioam6_fill_trace_data() then positions the write cursor without reserving the schema area but still copies the 4-byte schema header and the full schema payload, overrunning the trace buffer. Keep sclen in an unsigned int so the remaining-space check and the write cursor calculation both see the full schema length.

Source published

8 May 2026 13:37:19 UTC

Source modified

19 Oct 2026 19:16:27 UTC

Observed here

23 Oct 2026 15:48:27 UTC

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CVSS 3.1 · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H