CVE-2026-97873

MEDIUMCVSS 5.3/10EPSS 0.26%

Last modified

CVE-2026-97873 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. In Bouncy Castle for Java before 1.86, the raw JCA provider's legacy PBES1 (PKCS#5 scheme 1) and PKCS#12 PBE families ran their password-based key derivation with an iteration count taken from untrusted input without bounding it, so a small input could dictate an arbitrary amount of work before anything could be verified. The AlgorithmParameters implementations (PKCS12PBE and its object identifier aliases, and PBKDF1) accepted any count from an encoded PKCS12PBEParams or PBEParameter, narrowing a value beyond the int range with intValue(), and every Cipher, Mac and SecretKeyFactory in these families derived with whatever count it was given, including one decoded by another provider's AlgorithmParameters, as when javax.crypto.EncryptedPrivateKeyInfo.getKeySpec() decrypts a PKCS#12 PBE-protected private key with BC. EPSS estimates a 0.26% chance of exploitation in the next 30 days.

Description

In Bouncy Castle for Java before 1.86, the raw JCA provider's legacy PBES1 (PKCS#5 scheme 1) and PKCS#12 PBE families ran their password-based key derivation with an iteration count taken from untrusted input without bounding it, so a small input could dictate an arbitrary amount of work before anything could be verified. The AlgorithmParameters implementations (PKCS12PBE and its object identifier aliases, and PBKDF1) accepted any count from an encoded PKCS12PBEParams or PBEParameter, narrowing a value beyond the int range with intValue(), and every Cipher, Mac and SecretKeyFactory in these families derived with whatever count it was given, including one decoded by another provider's AlgorithmParameters, as when javax.crypto.EncryptedPrivateKeyInfo.getKeySpec() decrypts a PKCS#12 PBE-protected private key with BC. Both the parameter parse and the derivations now reject a negative or over-limit count under the org.bouncycastle.pbe.max_iteration_count property (default 10,000,000) that already bounded PBKDF2 (CVE-2026-17508), and the parse rejects a count beyond the int range rather than narrowing it. This issue also affects Bouncy Castle for Java LTS before 2.73.13.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Legion of the Bouncy Castle Inc.BC-JAVA< 1.86
Legion of the Bouncy Castle Inc.BC-LTS-JAVA>= 2.73.0, < 2.73.13

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-97873?
In Bouncy Castle for Java before 1.86, the raw JCA provider's legacy PBES1 (PKCS#5 scheme 1) and PKCS#12 PBE families ran their password-based key derivation with an iteration count taken from untrusted input without bounding it, so a small input could dictate an arbitrary amount of work before anything could be verified. The AlgorithmParameters implementations (PKCS12PBE and its object identifier aliases, and PBKDF1) accepted any count from an encoded PKCS12PBEParams or PBEParameter, narrowing a value beyond the int range with intValue(), and every Cipher, Mac and SecretKeyFactory in these families derived with whatever count it was given, including one decoded by another provider's AlgorithmParameters, as when javax.crypto.EncryptedPrivateKeyInfo.getKeySpec() decrypts a PKCS#12 PBE-protected private key with BC. Both the parameter parse and the derivations now reject a negative or over-limit count under the org.bouncycastle.pbe.max_iteration_count property (default 10,000,000) that already bounded PBKDF2 (CVE-2026-17508), and the parse rejects a count beyond the int range rather than narrowing it. This issue also affects Bouncy Castle for Java LTS before 2.73.13.
How severe is CVE-2026-97873?
CVE-2026-97873 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.
How do I fix CVE-2026-97873?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST