Unbounded PBE iteration count when decrypting PKCS#8 private keys
Summary
| CVE | CVE-2026-63578 |
|---|---|
| State | PUBLISHED |
| Assigner | bcorg |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-02 08:17:03 UTC |
| Updated | 2026-10-02 08:17:03 UTC |
| Description | Allocation of resources without limits in password-based private-key decryption (PbeUtilities.GenerateCipherParameters) in Legion of the Bouncy Castle Inc. bc-csharp before 2.7.0 allows an attacker who can supply an encrypted private key, such as a PKCS#8 EncryptedPrivateKeyInfo or "ENCRYPTED PRIVATE KEY" PEM file, to cause a denial of service through CPU exhaustion via an iteration count close to 2^31, because the count is taken from the unauthenticated algorithm parameters without an upper bound and the key derivation runs before the password or the data can be checked. PKCS#5 PBES1 and PBES2 (PBKDF2), the PKCS#12 PBE algorithms and CMS password recipients (CmsPbeKey) are affected. Loading PKCS#12 files with Pkcs12Store is covered by CVE-2026-63572, and a zero or negative count with the PKCS#12 algorithms by CVE-2026-63575. |
Risk And Classification
Primary CVSS: v4.0 7.1 HIGH from 91579145-5d7b-4cc5-b925-a0262ff19630
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Problem Types: CWE-770 | CWE-770 CWE-770 Allocation of Resources Without Limits or Throttling
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 91579145-5d7b-4cc5-b925-a0262ff19630 | Secondary | 7.1 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 7.1 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
NonePrivileges Required
NoneUser Interaction
PassiveConfidentiality
NoneIntegrity
NoneAvailability
HighSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Legion Of The Bouncy Castle Inc. | Bc-csharp | affected 2.7.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/bcgit/bc-csharp/commit/c00fc018fca89c077c64dd2a2a2eb00ae7d97241 | 91579145-5d7b-4cc5-b925-a0262ff19630 | github.com | |
| github.com/bcgit/bc-csharp/commit/b57165ecb7790ecea08273b219d52d80c12990e4 | 91579145-5d7b-4cc5-b925-a0262ff19630 | github.com | |
| github.com/bcgit/bc-csharp/commit/7c0ed15f9783c9595b1a53f3900136461fd944f4 | 91579145-5d7b-4cc5-b925-a0262ff19630 | github.com | |
| github.com/bcgit/bc-csharp/commit/54ea0b179ee627027829b44c45d6dd32e575bd67 | 91579145-5d7b-4cc5-b925-a0262ff19630 | github.com | |
| github.com/bcgit/bc-csharp/wiki/CVE-2026-63578 | 91579145-5d7b-4cc5-b925-a0262ff19630 | github.com | |
| github.com/bcgit/bc-csharp/commit/34a7c05f719c91c024f285c6b420d3c00f8019dd | 91579145-5d7b-4cc5-b925-a0262ff19630 | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Discovered by Claude, Anthropic's AI assistant, and triaged by the Anthropic security team in collaboration with Anthropic Research. (en)
There are currently no legacy QID mappings associated with this CVE.