Memory allocation with excessive size value in the HSS/LMS signature code (HssPublicKeyParameters, HssSignature) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker who can supply both an HSS public key and a signature to cause a denial of service through memory exhaustion via a public key encoding with an excessive level count, because the level count L read when parsing an HSS public key was not checked against the RFC 8554 maximum of 8, and signature parsing then allocated an array of L - 1 entries before reading any further signature data. A single verification can commit up to about 17 GB of memory or fail with an OutOfMemoryException.
Metrics
Affected Vendors & Products
References
History
Wed, 28 Oct 2026 13:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Bouncycastle
Bouncycastle bc-csharp |
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| CPEs | cpe:2.3:a:bouncycastle:bc-csharp:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Bouncycastle
Bouncycastle bc-csharp |
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| Metrics |
cvssV3_1
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Sun, 04 Oct 2026 22:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Legion Of The Bouncy Castle Inc.
Legion Of The Bouncy Castle Inc. bc-csharp |
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| Vendors & Products |
Legion Of The Bouncy Castle Inc.
Legion Of The Bouncy Castle Inc. bc-csharp |
Sat, 03 Oct 2026 06:30:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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Fri, 02 Oct 2026 07:30:00 +0000
| Type | Values Removed | Values Added |
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| Description | Memory allocation with excessive size value in the HSS/LMS signature code (HssPublicKeyParameters, HssSignature) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows a remote unauthenticated attacker who can supply both an HSS public key and a signature to cause a denial of service through memory exhaustion via a public key encoding with an excessive level count, because the level count L read when parsing an HSS public key was not checked against the RFC 8554 maximum of 8, and signature parsing then allocated an array of L - 1 entries before reading any further signature data. A single verification can commit up to about 17 GB of memory or fail with an OutOfMemoryException. | |
| Title | Unbounded HSS public key level count allows huge array allocation during signature verification | |
| Weaknesses | CWE-789 | |
| References |
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| Metrics |
cvssV4_0
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Status: PUBLISHED
Assigner: bcorg
Published: 2026-10-02T07:10:34.017Z
Updated: 2026-10-02T17:44:48.251Z
Reserved: 2026-09-30T23:01:10.053Z
Link: CVE-2026-103603
Updated: 2026-10-02T17:44:44.519Z
Status : Analyzed
Published: 2026-10-02T08:17:00.837
Modified: 2026-10-28T13:29:12.200
Link: CVE-2026-103603
No data.