CVE-2026-23243
What it is
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
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-787 · Out-of-bounds write
- Record status
- Modified
Affected
- Linux Kernel < 5.10.252
- Linux Kernel < 5.15.202
- Linux Kernel < 6.1.165
- Linux Kernel < 6.6.128
- Linux Kernel < 6.12.75
- Linux Kernel < 6.18.14
- Linux Kernel < 6.19.4
- Linux Kernel 2.6.24
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-23243.md and follow it. Check whether this project is affected by CVE-2026-23243. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- 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
References
- 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
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html