CVE-2026-63570: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') in Legion of the Bouncy Castle Inc. bc-csharp
Loop with unreachable exit condition in Pkcs12Store.GetCertificateChain in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply a crafted PKCS#12 file to an application that loads it and requests a key entry's certificate chain to cause a denial of service, in which the call never returns and consumes CPU and memory until an OutOfMemoryException, via certificates whose issuer links form a cycle, for example two certificates whose AuthorityKeyIdentifier extensions each identify the other's public key. This happens because the chain-building loop stops only when no issuer is found or a certificate links to itself, and keeps no record of certificates already visited. The key-identifier links are followed without checking signatures.
AI Analysis
Technical Summary
The vulnerability arises from a loop in the Pkcs12Store.GetCertificateChain function that fails to detect cycles in certificate issuer chains. Specifically, if certificates reference each other via AuthorityKeyIdentifier extensions forming a cycle, the chain-building loop never terminates because it only stops when no issuer is found or a certificate links to itself. The implementation does not track visited certificates and does not verify signatures on key-identifier links, allowing an attacker to supply a crafted PKCS#12 file that triggers an infinite loop and resource exhaustion.
Potential Impact
An attacker who can supply a malicious PKCS#12 file to an application using bc-csharp before 2.7.0 can cause a denial of service by triggering an infinite loop during certificate chain retrieval. This leads to high CPU and memory consumption until the application throws an OutOfMemoryException, potentially disrupting service availability.
Mitigation Recommendations
A fix is available in version 2.7.0 of bc-csharp. Users should upgrade to version 2.7.0 or later to remediate this vulnerability. No other mitigation guidance is provided.
CVE-2026-63570: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') in Legion of the Bouncy Castle Inc. bc-csharp
Description
Loop with unreachable exit condition in Pkcs12Store.GetCertificateChain in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply a crafted PKCS#12 file to an application that loads it and requests a key entry's certificate chain to cause a denial of service, in which the call never returns and consumes CPU and memory until an OutOfMemoryException, via certificates whose issuer links form a cycle, for example two certificates whose AuthorityKeyIdentifier extensions each identify the other's public key. This happens because the chain-building loop stops only when no issuer is found or a certificate links to itself, and keeps no record of certificates already visited. The key-identifier links are followed without checking signatures.
CVSS v4.0
Score 7.1high
Affected software
Legion of the Bouncy Castle Inc.
bc-csharp
pkg:nuget/BouncyCastle.CryptographyRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability arises from a loop in the Pkcs12Store.GetCertificateChain function that fails to detect cycles in certificate issuer chains. Specifically, if certificates reference each other via AuthorityKeyIdentifier extensions forming a cycle, the chain-building loop never terminates because it only stops when no issuer is found or a certificate links to itself. The implementation does not track visited certificates and does not verify signatures on key-identifier links, allowing an attacker to supply a crafted PKCS#12 file that triggers an infinite loop and resource exhaustion.
Potential Impact
An attacker who can supply a malicious PKCS#12 file to an application using bc-csharp before 2.7.0 can cause a denial of service by triggering an infinite loop during certificate chain retrieval. This leads to high CPU and memory consumption until the application throws an OutOfMemoryException, potentially disrupting service availability.
Mitigation Recommendations
A fix is available in version 2.7.0 of bc-csharp. Users should upgrade to version 2.7.0 or later to remediate this vulnerability. No other mitigation guidance is provided.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- bcorg
- Date Reserved
- 2026-07-16T23:48:46.076Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6abf5de5a43b0b3b8988e879
Added to database: 10/02/2026, 07:31:49 UTC
Last enriched: 10/02/2026, 07:46:43 UTC
Last updated: 10/02/2026, 22:45:56 UTC
Views: 11
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