CVE-2026-59651: bouncycastle bc-java Inadequate Encryption Strength
CVSS: 7.5v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-59651DEBIAN-CVE-2026-59651
Published 03-08-2026Last modified 03-08-2026
Vulnerability summary
CVE-2026-59651 is a high (CVSS 7.5) Inadequate Encryption Strength vulnerability in bouncycastle bc-java. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.3% of scored vulnerabilities.
CVSS score
7.5/10
010
High · v3.1 (NVD)EPSS score
0.24%
0%100%
Low · +0.08 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 5 · Related 5Timeline
- 03-08-2026PublishedVulnerability first disclosed.
- 03-08-2026Last modifiedVulnerability information updated.
Description
In Bouncy Castle for Java before 1.85, BKS keystore accepts legacy version with 16-bit integrity MAC key. This issue also affects Bouncy Castle for Java LTS before 2.73.12.
CVSS metrics
6 scores · 4 sources · 2 versionsHigh 7.1Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:AmberSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated7.1HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber
- NVDNIST7.1HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/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:Amber
High 7.5Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
14%
Versus all other CVEs
30-day change
+0.08 pp
From 0.16% on 19-09-2026
19-09-202619-10-2026
EPSS score0.24%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Bouncycastle2 products
- bc-java< 1.85
- bouncy_castle_for_java_lts≤ 2.73.11
Legion of the bouncy castle inc.2 products
- bc-java< 1.85
- bc-lts-java≥ 2.73.0, < 2.73.12
Debian1 product
- bouncycastleAll versions (No fix recorded) | < 1.86-1
Ubuntu1 product
- bouncycastleAll versions (No fix recorded)
4 vendors · 6 products
References
5 links- github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059651Vendor AdvisoryREPORTThird Party Advisory
