How severe is CVE-2026-59651?

CVE-2026-59651 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-59651 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-59651?

CVE-2026-59651 primarily affects Bouncycastle Bc-java. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-59651?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-59651 published?

CVE-2026-59651 was published on 2026-08-03 and last updated on 2026-09-02.

CVE-2026-59651

CVE-2026-59651 is a high-severity vulnerability in Bouncycastle Bc-java with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-326.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 7.1
EPSS exploit prediction: 0% (6th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-326
Affected product: Bouncycastle Bc-java
Published: 2026-08-03
Last modified: 2026-09-02

Description

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.

Frequently asked questions

What is CVE-2026-59651?: 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.
How severe is CVE-2026-59651?: CVE-2026-59651 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-59651 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (6th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-59651?: CVE-2026-59651 primarily affects Bouncycastle Bc-java. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-59651?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-59651 published?: CVE-2026-59651 was published on 2026-08-03 and last updated on 2026-09-02.

References

Affected products (2)

cpe:2.3:a:bouncycastle:bc-java:*:*:*:*:*:*:*:*
cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts:*:*:*:*:*:*:*:*

More vulnerabilities in Bouncycastle Bc-java

CVE-2007-6721 — Critical (CVSS 10.0): The Legion of the Bouncy Castle Java Cryptography API before release 1.38, as used in Crypto Provider Package before…
CVE-2018-1000613 — Critical (CVSS 9.8): Legion of the Bouncy Castle Legion of the Bouncy Castle Java Cryptography APIs 1.58 up to but not including 1.60…
CVE-2026-58062 — Critical (CVSS 9.1): In Bouncy Castle for Java before 1.85, Stapled OCSP response accepted without binding to the checked certificate. This…
CVE-2026-8763 — Critical (CVSS 9.1): In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI. This issue also…
CVE-2026-59650 — Critical (CVSS 9.1): In Bouncy Castle for Java before 1.85, MTI/A0 DH agreement exponentiates unvalidated peer value. This issue also…
CVE-2026-12817 — High (CVSS 8.6): In Bouncy Castle for Java before 1.85, OpenPGP AEAD decryption skips final tag on chunk-aligned data. This issue also…

All CVEs affecting Bouncycastle Bc-java →

Other CWE-326 (Inadequate Encryption Strength) vulnerabilities

CVE-2026-44523 — Critical (CVSS 10.0): Note Mark is an open-source note-taking application. Prior to 0.19.4, no minimum length or entropy is enforced on the…
CVE-2020-6966 — Critical (CVSS 10.0): In ApexPro Telemetry Server Versions 4.2 and prior, CARESCAPE Telemetry Server v4.2 & prior, Clinical Information…
CVE-2014-9199 — Critical (CVSS 10.0): The Clorius Controls Java web client before 01.00.0009g allows remote attackers to discover credentials by sniffing the…
CVE-2026-74889 — Critical (CVSS 9.8): openssl_encrypt versions before 1.4.0 use HKDF with no salt and static info parameter in key normalization functions,…
CVE-2018-25272 — Critical (CVSS 9.8): ELBA5 5.8.0 contains a remote code execution vulnerability that allows attackers to obtain database credentials and…
CVE-2025-12478 — Critical (CVSS 9.8): Non-Compliant TLS Configuration.This issue affects BLU-IC2: through 1.19.5; BLU-IC4: through 1.19.5 .

Browse all CWE-326 (Inadequate Encryption Strength) vulnerabilities →