# CVE-2026-63578: Bouncy Castle Cryptography unbounded resource allocation in password-based key decryption

Source: https://junglewise.ai/threats/cve-2026-63578-allocation-of-resources-without-limits-in-password-based-private  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-02. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-63578 · Severity: info · Published 2026-10-02

The Bouncy Castle Cryptography Library is a .NET cryptographic library used to encrypt private keys and handle secure communications. An attacker who can provide a specially crafted encrypted private key file can cause a denial of service by forcing the library to consume excessive CPU resources during key decryption, impacting any application using this library to load encrypted keys.

Technologies: [Legion of the Bouncy Castle BouncyCastle.Cryptography](https://junglewise.ai/threats/technologies/legion-of-the-bouncy-castle-bouncycastle-cryptography). Vendors: [Legion of the Bouncy Castle](https://junglewise.ai/threats/vendors/legion-of-the-bouncy-castle).

## Quick answers

**Is CVE-2026-63578 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-63578 being exploited in the wild.

**How severe is CVE-2026-63578?** Informational severity, published 2 October 2026.

**Which products and versions are affected?** Legion of the Bouncy Castle BouncyCastle.Cryptography before 2.7.0.

**Is there a fix for CVE-2026-63578?** Yes: fixed in BouncyCastle.Cryptography 2.7.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-63578 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-63578?** Check whether you run Legion of the Bouncy Castle BouncyCastle.Cryptography at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in BouncyCastle.Cryptography 2.7.0

## Technical details

The vulnerability exists in PbeUtilities.GenerateCipherParameters and related password-based encryption (PBES1, PBES2/PBKDF2, PKCS#12 PBE, and CMS password recipients) functions, which fail to validate the iteration count parameter before performing key derivation. An attacker supplying an encrypted private key with an iteration count close to 2^31 can trigger CPU exhaustion. The key derivation computation occurs before any password or data validation, making the attack trivial to execute.

## Affected products

- Legion of the Bouncy Castle BouncyCastle.Cryptography before 2.7.0

## Timeline

- 2026-10-02: disclosed

## References

- [https://www.nuget.org/packages/BouncyCastle.Cryptography](https://www.nuget.org/packages/BouncyCastle.Cryptography)
- [https://github.com/bcgit/bc-csharp/commit/34a7c05f719c91c024f285c6b420d3c00f8019dd](https://github.com/bcgit/bc-csharp/commit/34a7c05f719c91c024f285c6b420d3c00f8019dd)

## Related threats

- [Bouncy Castle improper certificate name-constraint validation](https://junglewise.ai/threats/cve-2026-63577-improper-certificate-validation-in-the-directoryname-name)
- [Bouncy Castle C# improper certificate validation in URI name constraints](https://junglewise.ai/threats/cve-2026-63576-improper-certificate-validation-in-pkixnameconstraintvalidator)
- [Bouncy Castle C# PKCS#12 key derivation denial of service](https://junglewise.ai/threats/cve-2026-63575-loop-with-unreachable-exit-condition-in-the-pkcs-12-key)
- [Bouncy Castle memory exhaustion in OpenPGP subpacket parsing](https://junglewise.ai/threats/cve-2026-63574-memory-allocation-with-excessive-size-value-in-the-openpgp)
- [Bouncy Castle RSA PKCS#1 v1.5 padding oracle in CMS key-transport](https://junglewise.ai/threats/cve-2026-63573-observable-discrepancy-in-the-cms-rsa-pkcs-1-v1-5-key-transport)