w1: therm: Fix off-by-one buffer overflow in alarms_store

Summary

In the Linux kernel, the following vulnerability has been resolved: w1: therm: Fix off-by-one buffer overflow in alarms_store The sysfs buffer passed to alarms_store() is allocated with 'size + 1' bytes and a NUL terminator is appended. However, the 'size' argument does not account for this extra byte. The original code then allocated 'size' bytes and used strcpy() to copy 'buf', which always writes one byte past the allocated buffer since strcpy() copies until the NUL terminator at index 'size'. Fix this by parsing the 'buf' parameter directly using simple_strtoll() without allocating any intermediate memory or string copying. This removes the overflow while simplifying the code.

Timeline

1. Feb 4, 2026, 4:07 PM UTCCVE published
2. Oct 15, 2026, 1:11 AM UTCRecord last updated

Affected versions

• Linux Linux

  From e2c94d6f572079511945e64537eb1218643f2e68 · fixed in 49ff9b4b9deacbefa6654a0a2bcaf910c9de7e95; From e2c94d6f572079511945e64537eb1218643f2e68 · fixed in 060b08d72a38b158a7f850d4b83c17c2969e0f6b; From e2c94d6f572079511945e64537eb1218643f2e68 · fixed in b3fc3e1f04dcc7c41787bbf08a6e0d2728e022cf; From e2c94d6f572079511945e64537eb1218643f2e68 · fixed in 6a5820ecfa5a76c3d3e154802c8c15f391ef442e; From e2c94d6f572079511945e64537eb1218643f2e68 · fixed in 6fd6d2a8e41b7f544a4d26cbd60bedf9c67893a0; From e2c94d6f572079511945e64537eb1218643f2e68 · fixed in e6b2609af21b5cccc9559339591b8a2cbf884169; From e2c94d6f572079511945e64537eb1218643f2e68 · fixed in 761fcf46a1bd797bd32d23f3ea0141ffd437668a

• Linux Linux

  5.8

• KernelLinux

  From 5.8.0 · fixed in 5.10.249; From 5.11.0 · fixed in 5.15.199; From 5.16.0 · fixed in 6.1.162; From 6.2.0 · fixed in 6.6.122; From 6.7.0 · fixed in 6.12.68; From 6.13.0 · fixed in 6.18.8

References 7