CVE-2026-46043 RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv
An integer underflow in the Linux kernel RDMA driver allows attackers to cause a denial of service via crafted packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46043?
CVE-2026-46043 is a critical vulnerability in Linux kernel, published on 27 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv
rxe_rcv() currently checks only that the incoming packet is at least header_size(pkt) bytes long before payload_size() is used.
However, payload_size() subtracts both the attacker-controlled BTH pad field and RXE_ICRC_SIZE from pkt->paylen:
payload_size = pkt->paylen - offset[RXE_PAYLOAD] - bth_pad(pkt) - RXE_ICRC_SIZE
This means a short packet can still make payload_size() underflow even if it includes enough bytes for the fixed headers. Simply requiring header_size(pkt) + RXE_ICRC_SIZE is not sufficient either, because a packet with a forged non-zero BTH pad can still leave payload_size() negative and pass an underflowed value to later receive-path users.
Fix this by validating pkt->paylen against the full minimum length required by payload_size(): header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE.
Weakness: CWE-190
Which versions are affected by CVE-2026-46043?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46043?
Apply the vendor's patch.
Is CVE-2026-46043 being exploited?
There is no known exploitation of CVE-2026-46043 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88455, BELL-CVE-2026-46043, DEBIAN-CVE-2026-46043, GHSA-ww3w-m544-ppj6, ROOT-OS-DEBIAN-11-CVE-2026-46043, ROOT-OS-DEBIAN-12-CVE-2026-46043 and 3 more.