UBUNTU-CVE-2026-92507: Use After Free
In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Fix potential use after free in ibdeallocpduser() When accessing a PD via the netlink path the only synchronization mechanism for the said PD is rdmarestrackget(). Currently, rdmarestrackdel() is invoked at the end of ibdeallocpduser(), which is too late, since by that point vendor-specific resources associated with the PD might already be freed. This can leave a short window where the PD remains accessible through restrack, leading to a potential use-after-free. Fix this by moving the rdmarestrackbegindel() call to the start of ibdeallocpduser(), ensuring that the PD is removed from restrack before its internal resources are released. This guarantees that no new users hold references to a PD that is in the process of destruction. In addition, this change preserves the intended inverted order between create and destroy routines: resources are added to restrack at the end of successful creation, and hence shall be removed from the restrack first thing during the destruction flow, which keeps the lifecycle management consistent and predictable.
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
Event History
Frequently Asked Questions
Which systems are exposed to this issue?
Systems using one of the listed Ubuntu Linux kernel packages may be exposed when RDMA protection domains are accessed through the netlink resource-tracking path. The affected lifecycle is specifically the userspace protection-domain deallocation path.
What access does an attacker need to exploit it?
The supplied severity vector indicates local access, low privileges, no user interaction, high attack complexity, and an additional required attack condition. Exploitation depends on racing access to a protection domain through RDMA resource tracking while that protection domain is being destroyed.
What is the impact if exploitation succeeds?
The issue can result in a use-after-free involving vendor-specific resources associated with an RDMA protection domain. The provided vector rates confidentiality, integrity, and availability impact as high.
What does the fix change?
The fix begins removal of the protection domain from RDMA resource tracking at the start of ib_dealloc_pd_user(), before internal vendor-specific resources are freed. This prevents new resource-tracking users from obtaining references while destruction is underway.