UBUNTU-CVE-2026-89528: Null Pointer Dereference
In the Linux kernel, the following vulnerability has been resolved: svcrdma: Reject Read lists that exceed the page budget Individual Read segment lengths are validated at decode time, but nothing prevents a requester from sending multiple segments whose cumulative length exceeds the rqpages array budget. When one segment fills the page array exactly, the runtime guard in svcrdmabuildreadsegment() is bypassed because len reaches zero. A subsequent segment then accesses the NULL sentinel slot at rqpages[rqmaxpages], resulting in a NULL pointer dereference during DMA mapping. Accumulate pages across all Read segments and reject the message at decode time when the total would overflow the page budget.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
In svcrdma message decoding, accumulate page usage across all Read segments and reject the message at decode time when the cumulative length would exceed the rq_pages page budget.
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using the affected Ubuntu Linux kernel packages are exposed when they provide the svcrdma service and process RDMA Read lists. The listed packages include linux, linux-azure, linux-aws-fips, linux-azure-fips, linux-fips, linux-gcp-fips, linux-gcp, and linux-oracle.
What does an attacker need to do to trigger the vulnerability?
An attacker needs to send an RDMA Read list containing multiple segments whose combined page usage exceeds the request page-array budget. No privileges or user interaction are required according to the supplied severity vector.
What is the likely impact of successful exploitation?
A crafted Read list can cause access to the NULL sentinel entry in the request page array during DMA mapping, producing a NULL pointer dereference. The supplied vector indicates an availability impact only.