Always-Incorrect Control Flow Implementation in Linux kernel - CVE-2026-98713

Vulnerability identifier: #VU157053

CSH Severity: Low

CVSS v4: 0 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98713

CWE-ID: CWE-670

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to trigger a spurious kernel warning through incorrectly handled guest instructions in arm64 KVM.

The vulnerability exists due to incorrect conditional gating of fine-grained undefined-instruction trap configuration in arm64 KVM when initializing nested virtualization traps on hardware without FEAT_FGT. A local privileged user can execute a TLBI OS instruction at guest vEL1 without FEAT_TLBIOS to reach handle_tlbi_el1(), which expects an EL1 TLBI only from vEL2, and trigger a kernel warning instead of the intended undefined-instruction exception.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-realtime (Ubuntu package)
linux-oracle (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-azure (Ubuntu package)
linux-raspi (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-azure-fde-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-gke (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-aws-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - update to 7.0.0-43.43
linux-realtime (Ubuntu package) - update to 7.0.0-43.43.1
linux-oracle (Ubuntu package) - update to 7.0.0-1016.18
linux-aws (Ubuntu package) - update to 7.0.0-1017.18
linux-gcp (Ubuntu package) - update to 7.0.0-1017.19
linux-azure (Ubuntu package) - update to 7.0.0-1020.21
linux-raspi (Ubuntu package) - update to 7.0.0-1023.23
linux-ibm (Ubuntu package) - update to 7.0.0-1018.18
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1016.18~24.04.1
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1017.19~24.04.1
linux-azure-fde-7.0 (Ubuntu package) - update to 7.0.0-1019.19~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1018.18
linux-gke (Ubuntu package) - update to 7.0.0-1010.11
linux-azure-fde (Ubuntu package) - update to 7.0.0-1019.19
linux-aws-7.0 (Ubuntu package) - update to 7.0.0-1017.18~24.04.1

• https://git.kernel.org/stable/c/1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087
• https://git.kernel.org/stable/c/2f4a15c52a552c5244ec27f4ca8bda855594f918
• https://git.kernel.org/stable/c/4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07
• https://git.kernel.org/stable/c/af3300b3a6bace925a496f3520e171c07b999c72

• Always-Incorrect Control Flow Implementation in Linux kernel arm64 kvm
• Ubuntu update for linux, linux-aws, linux-gcp and more
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws-7.0, linux-azure-fde, linux-azure-fde-7.0 and more
• Ubuntu update for linux-raspi