Legacy PBES1 and PKCS#12 PBE iteration count honoured unbounded in the raw JCA provider

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.

Scores

EPSS (exploitation in 30 days)

0.26% · top 82% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.

Weakness

• CWE-770 Allocation of Resources Without Limits or Throttling (opens in a new tab)All about CWE-770 and its CVEs

Affected products

• Legion of the Bouncy Castle Inc. · BC-JAVA

  • affected < 1.86

• Legion of the Bouncy Castle Inc. · BC-LTS-JAVA

  • affected 2.73.0 – < 2.73.13

References (2)

• https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9097873 (opens in a new tab)vendor-advisory
• https://github.com/bcgit/bc-java/commit/766a31026ac24ed3c6cad8662058ba450c338da1 (opens in a new tab)patch

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-97873](https://trackcve.app/badge/CVE-2026-97873.svg)](https://trackcve.app/cve/CVE-2026-97873)

Record last updated 5 Oct 2026, 17:00 UTC.