CVE Vulnerabilities

CVE-2025-49087

Covert Timing Channel

Published: Jul 20, 2025 | Modified: Aug 07, 2025
CVSS 3.x
3.7
LOW
Source:
NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 2.x
RedHat/V2
RedHat/V3
Ubuntu
MEDIUM

In Mbed TLS 3.6.1 through 3.6.3 before 3.6.4, a timing discrepancy in block cipher padding removal allows an attacker to recover the plaintext when PKCS#7 padding mode is used.

Weakness

Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information.

Affected Software

Name Vendor Start Version End Version
Mbed_tls Arm 3.6.1 (including) 3.6.4 (excluding)
Mbedtls Ubuntu upstream *

Extended Description

In some instances, knowing when data is transmitted between parties can provide a malicious user with privileged information. Also, externally monitoring the timing of operations can potentially reveal sensitive data. For example, a cryptographic operation can expose its internal state if the time it takes to perform the operation varies, based on the state. Covert channels are frequently classified as either storage or timing channels. Some examples of covert timing channels are the system’s paging rate, the time a certain transaction requires to execute, and the time it takes to gain access to a shared bus.

Potential Mitigations

References