CVE-2026-23243 PUBLISHED

RDMA/umad: Reject negative data_len in ib_umad_write

Assigner: Linux
Reserved: 13.01.2026 Published: 18.03.2026 Updated: 18.03.2026

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

RDMA/umad: Reject negative data_len in ib_umad_write

ib_umad_write computes data_len from user-controlled count and the MAD header sizes. With a mismatched user MAD header size and RMPP header length, data_len can become negative and reach ib_create_send_mad(). This can make the padding calculation exceed the segment size and trigger an out-of-bounds memset in alloc_send_rmpp_list().

Add an explicit check to reject negative data_len before creating the send buffer.

KASAN splat: [ 211.363464] BUG: KASAN: slab-out-of-bounds in ib_create_send_mad+0xa01/0x11b0 [ 211.364077] Write of size 220 at addr ffff88800c3fa1f8 by task spray_thread/102 [ 211.365867] ib_create_send_mad+0xa01/0x11b0 [ 211.365887] ib_umad_write+0x853/0x1c80

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to 1371ef6b1ecf3676b8942f5dfb3634fb0648128e (excl.)
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to 362e45fd9069ffa1523f9f1633b606ebf72060d7 (excl.)
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to 6eb2919474ca105c5b13d19574e25f0ddcf19ca2 (excl.)
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0d (excl.)
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to 9c80d688f402539dfc8f336de1380d6b4ee14316 (excl.)
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to 205955f29c26330b1dc7fdeadd5bb97c38e26f56 (excl.)
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to 52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34b (excl.)
  • affected from 2be8e3ee8efd6f99ce454115c29d09750915021a to 5551b02fdbfd85a325bb857f3a8f9c9f33397ed2 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 2.6.24 is affected
  • unaffected from 0 to 2.6.24 (excl.)
  • unaffected from 5.10.252 to 5.10.* (incl.)
  • unaffected from 5.15.202 to 5.15.* (incl.)
  • unaffected from 6.1.165 to 6.1.* (incl.)
  • unaffected from 6.6.128 to 6.6.* (incl.)
  • unaffected from 6.12.75 to 6.12.* (incl.)
  • unaffected from 6.18.14 to 6.18.* (incl.)
  • unaffected from 6.19.4 to 6.19.* (incl.)
  • unaffected from 7.0-rc1 to * (incl.)

References