CVE-2025-23149 is a vulnerability identified in the Linux kernel's Trusted Platform Module (TPM) driver subsystem. Specifically, the flaw arises from improper handling of the TPM chip state during system suspend and resume cycles. The vulnerability occurs because the kernel does not correctly check the TPM_CHIP_FLAG_SUSPENDED flag after invoking tpm_find_get_ops(), which can lead to an erroneous call to tpm_chip_start() while the TPM chip is still marked as suspended. This results in attempts to perform I2C transfers to the TPM chip during suspend, which is unsupported and triggers kernel warnings and potentially unstable behavior. The provided kernel log snippet shows a warning triggered by an I2C transfer during suspend, with a stack trace pointing to the TPM driver functions such as tpm_cr50_i2c_transfer_message and tpm_chip_start. The root cause is that tpm_chip_start() should not be called within tpm_try_get_ops() if the TPM_CHIP_FLAG_SUSPENDED flag is set, as tpm_find_get_ops() will return NULL in such cases. Failure to enforce this leads to spurious TPM chip start attempts during suspend, which can cause kernel warnings, potential crashes, or undefined behavior. Although no known exploits are reported in the wild, this vulnerability could be leveraged to cause denial of service or kernel instability on affected Linux systems. The affected versions include several recent Linux kernel commits identified by their hashes, indicating this is a recent regression or bug introduced in newer kernel versions. No CVSS score has been assigned yet, and no patches are linked in the provided data, but the issue is publicly disclosed and marked as published as of May 1, 2025.

For European organizations, this vulnerability poses a risk primarily to systems running affected Linux kernel versions with TPM hardware enabled, especially those relying on TPM for security functions such as hardware-based key storage, secure boot, or cryptographic operations. The improper handling of TPM chip state during suspend could lead to kernel instability or crashes, resulting in denial of service conditions. This is particularly impactful for critical infrastructure, industrial control systems, and enterprise servers that require high availability and rely on TPM for security assurances. Organizations using Linux-based endpoints, servers, or embedded devices with TPM chips could experience unexpected reboots or system faults, potentially disrupting business operations or security services. Although exploitation does not appear to allow privilege escalation or data leakage directly, the stability issues could be leveraged by attackers to cause service interruptions or to facilitate further attacks by destabilizing the system. Given the widespread use of Linux in European data centers, cloud providers, and governmental IT infrastructure, the vulnerability could have broad operational impacts if unmitigated.

To mitigate CVE-2025-23149, European organizations should: 1) Immediately identify and inventory Linux systems running affected kernel versions with TPM enabled. 2) Apply the official Linux kernel patches once released that properly check the TPM_CHIP_FLAG_SUSPENDED flag before calling tpm_chip_start(), preventing spurious TPM starts during suspend. 3) Temporarily disable TPM support or suspend/resume functionality on critical systems if patching is not immediately feasible, to avoid triggering the vulnerability. 4) Monitor kernel logs for warnings related to I2C transfers during suspend or TPM chip start failures as indicators of attempted exploitation or system instability. 5) Coordinate with Linux distribution vendors and hardware manufacturers to ensure timely updates and firmware compatibility. 6) Implement robust system monitoring and automated reboot mechanisms to minimize downtime in case of kernel crashes. 7) For high-security environments, consider isolating vulnerable systems or restricting access until patched to reduce risk of denial of service attacks.