In the Linux kernel, the following vulnerability has been resolved: RDMA/umad: Reject negative...

CVE-2026-23243 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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

Basic information

Type
unreviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Not specified
Published (advisory)
2026-03-18 12:31:52 UTC
Updated
2026-07-14 15:31:40 UTC
NVD published
2026-03-18

EPSS Score

Score Percentile
0.13% 3.03%

CVSS Scores

Base score Version Severity Vector
7.8 3.1 —
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-85rq-57vx-88q2 ↗
CVE CVE-2026-23243 ↗

CWEs

CWE id Name
CWE-787 Out-of-bounds Write

References

cvelogic Threat Intelligence