Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:AmberCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-59651 is a high-severity Inadequate Encryption Strength (CWE-326) vulnerability in Bouncycastle Bc-Java. Its CVSS base score is 7.1 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Brute Force (T1110); ranked at the 6th 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-13 (Cryptographic Protection) and SC-12 (Cryptographic Key Establishment and Management) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-52023
Vulnerability Data
In Bouncy Castle for Java before 1.85, BKS keystore accepts legacy version with 16-bit integrity MAC key. This issue also affects Bouncy Castle for Java LTS before 2.73.12.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 12 hardening rules · 6 OS baselines
V11.4.2V14.1.2V14.2.4
Mitigating Controls (NIST 800-53 r5) AI
SC-13 requires selection and implementation of specific cryptographic algorithms and key lengths, directly preventing use of inadequate encryption strength.
SC-12 governs cryptographic key establishment and management, which can enforce sufficient key sizes and thereby reduce inadequate encryption strength.
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.
Strong encryption is required to protect confidentiality of data-at-rest.
Strong encryption is required to protect confidentiality of data-in-transit.
Hardened baselines can enforce minimum cryptographic algorithm and key-length settings.
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.
Requiring the organization to define and enforce minimum cryptographic strength prevents deployment of insufficient key lengths or weak ciphers that can be brute-forced.
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` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 9 (1 rule)
- V-271756 OL 9 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. prevents CWE-326
RHEL 8 (1 rule)
- V-230224 All RHEL 8 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. prevents CWE-326
RHEL 9 (1 rule)
- V-257879 RHEL 9 local disk partitions must implement cryptographic mechanisms to prevent unauthorized disclosure or modification of all information that requires at rest protection. prevents CWE-326
Windows Server 2016 (1 rule)
- V-224843 Systems requiring data at rest protections must employ cryptographic mechanisms to prevent unauthorized disclosure and modification of the information at rest. prevents CWE-326