CVE-2020-15522

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.

Published: 2021-05-20 Last update: 2025-07-17 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2020-15522 is rated Moderate Risk (49.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.52%). Core evidence: EPSS rose +1.12% over the last day, indicating growing attacker interest. Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-15522

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.40% 1.52% +1.12%
2 2026-04-24 0.57% 0.40% -0.17%
3 2026-03-04 0.57%

Full EPSS history (50 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-15522

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
2.2 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-15522

GitHub Security Advisory for CVE-2020-15522

GHSA-6xx3-rg99-gc3p · Severity: medium · Ecosystem: maven — Timing based private key exposure in Bouncy Castle

OS Trackers for CVE-2020-15522

vendor priority summary link
debian not yet assigned CVE-2020-15522 not yet assigned priority: Debian including 1 source packages (bouncycastle), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-15522
redhat medium https://access.redhat.com/security/cve/CVE-2020-15522
suse medium CVE-2020-15522 severity moderate: SUSE including 40 source package names (3.3.2-2.3:bouncycastle-1.71-150200.3.9.4, 3.3.2-2.3:bouncycastle-pkix-1.71-150200.3.9.4, …), 115 product×package rows across 26 product lines (Container containers/apache-pulsar, SUSE Enterprise Storage 7, … (26 product lines)): Fixed 115. https://www.suse.com/security/cve/CVE-2020-15522/
ubuntu medium CVE-2020-15522 medium priority: Ubuntu including 1 source packages (bouncycastle), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 10, ignored 4, DNE 1, released 1. https://ubuntu.com/security/CVE-2020-15522

Affected software / configurations for CVE-2020-15522

Vendor Product Version Raw CPE
bouncycastle bc-csharp < 1.8.7 cpe:2.3:a:bouncycastle:bc-csharp:*:*:*:*:*:*:*:*
bouncycastle bouncy_castle_fips_.net_api < 1.0.1.1 cpe:2.3:a:bouncycastle:bouncy_castle_fips_.net_api:*:*:*:*:*:*:*:*
bouncycastle fips_java_api < 1.0.1.2 cpe:2.3:a:bouncycastle:fips_java_api:*:*:*:*:*:*:*:*
bouncycastle fips_java_api >= 1.0.2, < 1.0.2.1 cpe:2.3:a:bouncycastle:fips_java_api:*:*:*:*:*:*:*:*
bouncycastle the_bouncy_castle_crypto_package_for_java < 1.66 cpe:2.3:a:bouncycastle:the_bouncy_castle_crypto_package_for_java:*:*:*:*:*:*:*:*

References for CVE-2020-15522

cvelogic Threat Intelligence