CVE-2026-25835
Arm Mbed Tls 2.18.0 – 3.6.6
Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NSummary
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 Forge Web Credentials (T1606); ranked at the 7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-12 (Cryptographic Key Establishment and Management) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
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/.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17999
Vulnerability Data
Mbed TLS before 3.6.6 and TF-PSA-Crypto before 1.1.0 misuse seeds in a Pseudo-Random Number Generator (PRNG).
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 2 hardening rules · 2 OS baselines
V7.2.3V11.5.1
Mitigating Controls (NIST 800-53 r5) AI
SC-12 requires proper establishment and management of cryptographic keys and material, which directly encompasses correct seeding of PRNGs used for cryptographic purposes.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly enforce correct PRNG seeding during development, though the control addresses many other coding issues as well.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect weak seeding but does not itself prevent the weakness.
Cryptography policy and key-management rules directly require proper seeding of PRNGs used for keys and nonces.
Secure-coding standards mandate correct PRNG seeding to avoid predictable random values.
Strong authentication mechanisms rely on unpredictable random values, indirectly requiring proper PRNG seeding.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248563 The OL 8 SSH server must be configured to use strong entropy. prevents CWE-335
RHEL 8 (1 rule)
- V-230253 RHEL 8 must ensure the SSH server uses strong entropy. prevents CWE-335