Out-of-bounds read in Linux kernel - CVE-2026-98728

Vulnerability identifier: #VU157075

CSH Severity: Low

CVSS v4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-98728

CWE-ID: CWE-125

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to disclose stale buffer contents through random bytes returned to a caller.

The vulnerability exists due to an out-of-bounds read in the Linux kernel's tpm2_get_random() function when processing a truncated TPM response carrying the TPM2_ST_SESSIONS tag. A local user can supply such a response to bypass a length check that fails to account for the skipped 4-byte parameter size field, causing memcpy() to read up to 4 bytes past the response end and copy stale buffer contents into the caller's random bytes.

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/42bb6216b861e892512128219ff23010d656ba14
• https://git.kernel.org/stable/c/9b522400bf5c082feb9a0037a053ea822a2c7e4d
• https://git.kernel.org/stable/c/be54101992c2c5218be0e0a87827ccc96e3089af
• https://git.kernel.org/stable/c/e30a2406408d2df6d9cd48c2e59e913cf266a05a

• Out-of-bounds read in Linux kernel char tpm driver
• 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