CVE-2026-25835
Published: 01 April 2026
Summary
CVE-2026-25835 is a high-severity PRNG (CWE-335) vulnerability in Arm Mbed Tls. Its CVSS base score is 7.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Reduce Key Space (T1600.001); ranked at the 3.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly remediates the PRNG seed misuse flaw by requiring identification, reporting, testing, and correction via upgrades to Mbed TLS 3.6.6 or TF-PSA-Crypto 1.1.0.
Vulnerability monitoring and scanning identifies systems running vulnerable Mbed TLS or TF-PSA-Crypto versions affected by predictable PRNG.
Requires cryptographic key establishment and management mechanisms that rely on properly seeded PRNGs, mitigating predictability from seed misuse.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability enables predictable/clonable RNG output via seed misuse (CWE-335), directly facilitating reduction of effective cryptographic key space for attacks on confidentiality/integrity.
NVD Description
Mbed TLS before 3.6.6 and TF-PSA-Crypto before 1.1.0 misuse seeds in a Pseudo-Random Number Generator (PRNG).
Deeper analysisAI
CVE-2026-25835 is a vulnerability in Mbed TLS versions prior to 3.6.6 and TF-PSA-Crypto versions prior to 1.1.0 that results from the misuse of seeds in a Pseudo-Random Number Generator (PRNG). This issue, published on 2026-04-01 and associated with CWE-335, carries a CVSS v3.1 base score of 7.7 (AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).
A local attacker can exploit this vulnerability with low attack complexity, requiring no privileges or user interaction. Exploitation enables high-impact compromise of confidentiality and integrity, such as through predictable or clonable random number generation, while leaving availability unaffected and scope unchanged.
The Mbed TLS security advisories detail mitigation, recommending upgrades to Mbed TLS 3.6.6 or later and TF-PSA-Crypto 1.1.0 or later. Relevant advisories are available at https://mbed-tls.readthedocs.io/en/latest/security-advisories/ and https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-rng-cloning/.
Details
- CWE(s)