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.
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Affected Vendors & Products
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Solution
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Workaround
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References
History
Fri, 02 Oct 2026 07:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | Unbounded ASN.1 nesting depth causes process-terminating stack overflow | |
| Weaknesses | CWE-674 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: bcorg
Published:
Updated: 2026-10-02T07:08:51.653Z
Reserved: 2026-09-30T23:01:10.053Z
Link: CVE-2026-103600
No data.
Status : Received
Published: 2026-10-02T08:17:00.363
Modified: 2026-10-02T08:17:00.363
Link: CVE-2026-103600
No data.
OpenCVE Enrichment
Updated: 2026-10-02T08:45:07Z
Weaknesses