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CVE-2026-23243
RDMA/umad: Reject negative data_len in ib_umad_write
Overview
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

Details
INFO

Published Date :

March 18, 2026, 11:16 a.m.

Last Modified :

March 18, 2026, 11:16 a.m.

Remotely Exploit :

No

Source :

416baaa9-dc9f-4396-8d5f-8c081fb06d67
Impact
Affected Products

The following products are affected by CVE-2026-23243 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

: Total Affected Vendor : 0 | Products : 0
Solution
Apply the Linux kernel patch to reject negative data_len in ib_umad_write to prevent out-of-bounds writes.
  • Update the Linux kernel to the latest version.
  • Apply the specific patch for RDMA/umad: Reject negative data_len.
  • Verify the fix by testing the impacted functionality.
  • Reboot the system after applying the kernel update.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-23243.

URL Resource
https://git.kernel.org/stable/c/1371ef6b1ecf3676b8942f5dfb3634fb0648128e
https://git.kernel.org/stable/c/205955f29c26330b1dc7fdeadd5bb97c38e26f56
https://git.kernel.org/stable/c/362e45fd9069ffa1523f9f1633b606ebf72060d7
https://git.kernel.org/stable/c/52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34b
https://git.kernel.org/stable/c/5551b02fdbfd85a325bb857f3a8f9c9f33397ed2
https://git.kernel.org/stable/c/6eb2919474ca105c5b13d19574e25f0ddcf19ca2
https://git.kernel.org/stable/c/9c80d688f402539dfc8f336de1380d6b4ee14316
https://git.kernel.org/stable/c/a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0d
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-23243 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-23243 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-23243 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-23243 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    Mar. 18, 2026

    Action Type Old Value New Value
    Added 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
    Added Reference https://git.kernel.org/stable/c/1371ef6b1ecf3676b8942f5dfb3634fb0648128e
    Added Reference https://git.kernel.org/stable/c/205955f29c26330b1dc7fdeadd5bb97c38e26f56
    Added Reference https://git.kernel.org/stable/c/362e45fd9069ffa1523f9f1633b606ebf72060d7
    Added Reference https://git.kernel.org/stable/c/52ab82cc5cf8ada5c3fb6ffe8f32fdb2fc27a34b
    Added Reference https://git.kernel.org/stable/c/5551b02fdbfd85a325bb857f3a8f9c9f33397ed2
    Added Reference https://git.kernel.org/stable/c/6eb2919474ca105c5b13d19574e25f0ddcf19ca2
    Added Reference https://git.kernel.org/stable/c/9c80d688f402539dfc8f336de1380d6b4ee14316
    Added Reference https://git.kernel.org/stable/c/a6a3e4af10993cb9e4b8f0548680aba0ab5f3b0d
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
No CVSS metrics available for this vulnerability.