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

Summary

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.

Timeline

1. May 8, 2026, 1:37 PM UTCCVE published
2. Oct 16, 2026, 3:16 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: total

3. Oct 19, 2026, 7:16 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 8c6f6fa6772696be0c047a711858084b38763728 · fixed in d3a1fb2ca323d7a4e10ab3afbfa25e6d8921e4f2; From 8c6f6fa6772696be0c047a711858084b38763728 · fixed in e96d48b37708d53cbdc47f6f60b0714fc4a5f596; From 8c6f6fa6772696be0c047a711858084b38763728 · fixed in d1b041080086e91d3733a5438a8c51ad5d3d8e09; From 8c6f6fa6772696be0c047a711858084b38763728 · fixed in 77695a69baca9b99d95fad09fc78c2318736604f; From 8c6f6fa6772696be0c047a711858084b38763728 · fixed in 184d2e9db27c0f76226b5cad16fe29510a5d2280; From 8c6f6fa6772696be0c047a711858084b38763728 · fixed in d6e1c9b02d85a4f1f4ba6d68e916d9b610a3ed7d; From 8c6f6fa6772696be0c047a711858084b38763728 · fixed in 5e67ba9bb531e1ec6599a82a065dea9040b9ce50

• Linux Linux

  5.15

• KernelLinux

  From 5.15.0 · fixed in 5.15.210; From 5.16.0 · fixed in 6.1.168; From 6.2.0 · fixed in 6.6.134; From 6.7.0 · fixed in 6.12.81; From 6.13.0 · fixed in 6.18.22; From 6.19.0 · fixed in 6.19.12

References 7