Is CVE-2026-63575 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-63575 being exploited in the wild.

How severe is CVE-2026-63575?

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-2026-63575?

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-2026-63575 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-63575?

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.

CVE-2026-63575: Bouncy Castle C# PKCS#12 key derivation denial of service

CVE-2026-63575 · Severity: info · Published 2026-10-02

Bouncy Castle's C# cryptography library, used to decrypt encrypted security keys and certificates, contains a flaw in how it processes PKCS#12 files. An attacker can craft a malicious certificate file with a negative iteration count that causes the library to loop billions of times, consuming CPU and making the system unresponsive for extended periods.

Technologies: Legion of the Bouncy Castle BouncyCastle.Cryptography. Vendors: Legion of the Bouncy Castle.

Quick answers

Is CVE-2026-63575 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-63575 being exploited in the wild.
How severe is CVE-2026-63575?: 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-2026-63575?: 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-2026-63575 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-63575?: 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 Pkcs12ParametersGenerator component contains an integer underflow vulnerability in its key derivation loop. When processing a PKCS#12 file with an iteration count ≤ 0, the loop condition allows the counter to wrap around approximately 2^32 iterations before terminating, causing CPU exhaustion. An attacker must supply a malicious PKCS#12 (PFX) file or PKCS#8 encrypted private key using PKCS#12 password-based encryption, with no authentication required.

Affected products

Legion of the Bouncy Castle BouncyCastle.Cryptography before 2.7.0

Timeline

2026-10-02: disclosed

References

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