Inefficient Algorithmic Complexity Affecting system.security.cryptography.pkcs package, versions [,8.0.2)[9.0.0-preview.1.24080.9,9.0.21)[10.0.0-preview.1.25080.5,10.0.13)[11.0.0-preview.1.26104.118,11.0.0-rc.2.26504.105)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DOTNET-SYSTEMSECURITYCRYPTOGRAPHYPKCS-20935726
- published14 Oct 2026
- disclosed13 Oct 2026
- creditDr.-Ing Ashar Javed
Introduced: 13 Oct 2026
NewCVE-2026-84008 (opens in a new tab)How to fix?
Upgrade System.Security.Cryptography.Pkcs to version 8.0.2, 9.0.21, 10.0.13, 11.0.0-rc.2.26504.105 or higher.
Overview
Affected versions of this package are vulnerable to Inefficient Algorithmic Complexity in the SignedCms.CheckSignature method, which reparses the X.509 data carried in the message rather than parsing it once, so the work grows quadratically with the number of embedded certificates. An attacker can exhaust CPU on the verifying host by submitting a signed message whose certificate collection is sized to maximize the repeated parsing. This requires an application that calls CheckSignature on CMS or PKCS#7 input it does not control, and it applies on Windows, Linux, and macOS across all architectures.