---
id: CVE-2026-63575
title: >-
  Loop with unreachable exit condition in the PKCS#12 key derivation
  (Pkcs12ParametersGenerator) in Legion of the Bouncy Castle Inc
summary: >-
  Loop with unreachable exit condition in the PKCS#12 key derivation
  (Pkcs12ParametersGenerator) in Legion of the Bouncy Castle Inc. bc-csharp
  before 2.7.0 allows an attacker who can supply a PKCS#12 (PFX) file, or a
  PKCS#8 encrypted priva…
severity: high
cvss: 7.1
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-835
vendor: Legion of the Bouncy Castle Inc.
product: BouncyCastle.Cryptography
affected:
  - BouncyCastle.Cryptography < 2.7.0
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T08:17:02.643'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63575'
references:
  - url: >-
      https://github.com/bcgit/bc-csharp/commit/0c7a6dfd64c4a479577e35a728a766721b79aba7
    label: 91579145-5d7b-4cc5-b925-a0262ff19630
  - url: >-
      https://github.com/bcgit/bc-csharp/commit/7c0ed15f9783c9595b1a53f3900136461fd944f4
    label: 91579145-5d7b-4cc5-b925-a0262ff19630
  - url: 'https://github.com/bcgit/bc-csharp/wiki/CVE-2026-63575'
    label: 91579145-5d7b-4cc5-b925-a0262ff19630
tags:
  - nvd
  - cve.org
cvssSource: cna
ingestedAt: '2026-10-02T08:14:06.228Z'
---

## Overview

Loop with unreachable exit condition in the PKCS#12 key derivation (Pkcs12ParametersGenerator) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply a PKCS#12 (PFX) file, or a PKCS#8 encrypted private key that uses a PKCS#12 password-based encryption algorithm, to cause a denial of service through CPU exhaustion via an iteration count of zero or below, because the derivation loop ran until its counter equalled the count, so for such a count it wrapped through about 2^32 iterations before the MAC or the password could be checked. A 75-byte PFX file with a negative MacData iteration count kept Pkcs12Store.Load busy for many minutes.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.