🛡️ CVE-2026-23243 on Debian — linux

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

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

Distribution advisory

This page covers CVE-2026-23243 as tracked by Debian, for the package linux. The fix is available in version 6.18.14-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

DEBIAN-CVE-2026-23243 is recorded against 2 packages.

linux (fixed in 6.18.14-1)
linux-6.1 (fixed in 6.1.170-1~deb11u1)

Timeline and source

Published on 18 March 2026 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2026-23243 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

BellSoft Base record Debian 11 (Root.io)Debian 12 (Root.io)Debian 13 (Root.io)Ubuntu 22.04 (Root.io)Ubuntu 24.04 (Root.io)Ubuntu

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2026-03-18

Updated 2026-08-12

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
linux	—	6.18.14-1
linux-6.1	—	6.1.170-1~deb11u1

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2026-23243

🔗 NVD 🔗 Mitre

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