Bouncy Castle BC Java before 1.66, BC C# .NET before 1.8.7, BC-FJA before 1.0.1.2, 1.0.2.1, and BC-FNA before 1.0.1.1 have a timing issue within the EC math library that can expose information about the private key when an attacker is able to observe timing information for the generation of multiple deterministic ECDSA signatures.
CVSS v4.0 Metrics
Exploitability
Attack VectorNetwork
ComplexityHigh
RequirementsPresent
PrivilegesNone
User InteractionNone
Threat
Exploit MaturityPoC
Vulnerable System
ConfidentialityHigh
IntegrityNone
AvailabilityNone
Subsequent System
ConfidentialityNone
IntegrityNone
AvailabilityNone
Supplemental
SafetyNegligible
AutomatableYes
RecoveryAutomatic
Value DensityConcentrated
UrgencyMedium
Change Log
| Date | Source | Changes | Score |
|---|
| 2026-07-21 | PoC | E: U→P | 4.6 → 6.9 |
| 2026-07-21 | nvd | AV: P→N, PR: H→N, UI: A→N, VC: N→H | 0.0 → 4.6 |
| 2026-07-21 | cve.org | initial, patch: Unavailable | 0.0 |
Affected Software
| Vendor | Product | Version |
|---|
| bouncycastle | bc-csharp | < 1.8.7 |
| bouncycastle | bouncy_castle_fips_.net_api | < 1.0.1.1 |
| bouncycastle | fips_java_api | ≥ 1.0.2, < 1.0.2.1 |
| bouncycastle | fips_java_api | < 1.0.1.2 |
| bouncycastle | the_bouncy_castle_crypto_package_for_java | < 1.66 |
Published: 2021-05-20
