Vulnerability Details CVE-2026-103600
Uncontrolled recursion in the ASN.1 parser (Asn1InputStream, Asn1StreamParser) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker to cause a denial of service via a crafted ASN.1 encoding of deeply nested constructed elements (for example SEQUENCE inside SEQUENCE, in definite-length DER or indefinite-length BER form), because each nesting level is parsed by a further recursive call with no bound on depth. About 2,000 levels (8 KB of DER) are enough to exhaust a 1.5 MB thread stack, the .NET main-thread default on Windows, and raise a StackOverflowException, which .NET cannot catch and which terminates the whole process; on threads with larger stacks, parse time instead grows quadratically with depth (about 9 seconds of CPU for a 64 KB input). Any path that parses untrusted ASN.1 is exposed, including X.509 certificates and CRLs, CMS/PKCS#7, PKCS#8/PKCS#12, OCSP and TLS Certificate messages.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.004
EPSS Ranking 29.7%
CVSS Severity
CVSS v3 Score 7.5
Products affected by CVE-2026-103600
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cpe:2.3:a:bouncycastle:bc-csharp:-
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cpe:2.3:a:bouncycastle:bc-csharp:1.7.0
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cpe:2.3:a:bouncycastle:bc-csharp:1.7.0.1
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cpe:2.3:a:bouncycastle:bc-csharp:1.7.0.2
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.0
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.1
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.10
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.2
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.3
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.4
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.5
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.6
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.7
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.8
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cpe:2.3:a:bouncycastle:bc-csharp:1.8.9
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cpe:2.3:a:bouncycastle:bc-csharp:1.9.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.0.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.1.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.1.1
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cpe:2.3:a:bouncycastle:bc-csharp:2.2.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.2.1
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cpe:2.3:a:bouncycastle:bc-csharp:2.3.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.3.1
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cpe:2.3:a:bouncycastle:bc-csharp:2.4.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.5.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.5.1
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cpe:2.3:a:bouncycastle:bc-csharp:2.6.0
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cpe:2.3:a:bouncycastle:bc-csharp:2.6.1
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cpe:2.3:a:bouncycastle:bc-csharp:2.6.2