CVE-2026-23243
Published: March 18, 2026· Updated: Mar 18, 2026
Official Description
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
Technical Analysis
CVE-2026-23243 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
Affected Vendors & Products
Exploit & PoC Resources
All References (8)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-23243 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts