CVE-2026-103603

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Source

https://cve.org/CVERecord?id=CVE-2026-103603

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-103603.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-103603

Published

2026-10-02T07:10:34Z

Modified

2026-10-03T03:46:08Z

Severity

8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator

Summary

Unbounded HSS public key level count allows huge array allocation during signature verification

Details

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.

Database specific

{
    "cna_assigner":  "bcorg",
    "cwe_ids":  [
        "CWE-789"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103603.json"
}

References

Affected packages

Git / github.com/bcgit/bc-csharp

Affected ranges

Type

GIT

Repo

https://github.com/bcgit/bc-csharp

Events

Introduced

Fixed

4007498b13582d90ee1eda5d9920c324428b98b3

Database specific

Show details

{
    "extracted_events":  [
        {
            "introduced":  "0"
        },
        {
            "fixed":  "2.7.0"
        }
    ],
    "source":  "AFFECTED_FIELD"
}

Affected versions

release-1.*

release-1.8.0

release-1.8.0-RC.1

release-1.8.0-RC.2

release-1.8.0-RC.3

release-1.8.0-beta.1

release-1.8.0-beta.2

release-1.8.0-beta.3

release-1.8.0-beta.4

release-1.8.1

release-1.8.10

release-1.8.2

release-1.8.3

release-1.8.4

release-1.8.5

release-1.8.6

release-1.8.7

release-1.8.8

release-1.9.0

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-103603.json"