CVE-2026-59650: bouncycastle bc-java Improper Input Validation
CVSS: 9.3v4.0CriticalAnalyzed
AliasesUBUNTU-CVE-2026-59650DEBIAN-CVE-2026-59650CGA-748c-f4v8-x977CGA-9mrq-f6hj-wj2qCGA-ffx2-q688-mc3fCGA-g5mp-p9jh-j2f2CGA-hj25-7pvx-vrvmCGA-qqr2-5r24-phcrCGA-vfgp-6q8f-cxqpCGA-w5fv-j464-qrg8CGA-3835-3259-hwqpCGA-7798-jmp6-r88mCGA-7q6j-m5mv-79qvCGA-cjw5-5fc2-6wx4CGA-mcmc-c62h-qwpvCGA-p62w-43gr-q227CGA-qj54-qgqj-62wqCGA-rh39-r2r7-24fp
Published 03-08-2026Last modified 03-08-2026
Vulnerability summary
CVE-2026-59650 is a critical (CVSS 9.3) Improper Input Validation vulnerability in bouncycastle bc-java. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 25.6% of scored vulnerabilities.
CVSS score
9.3/10
010
Critical · v4.0 (CVE.org)EPSS score
0.34%
0%100%
Low · +0.07 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, MTI/A0 DH agreement exponentiates unvalidated peer value. This issue also affects Bouncy Castle for Java LTS before 2.73.12.
CVSS metrics
8 scores · 6 sources · 2 versionsCritical 9.3Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:AmberSourcesAll 5 agree
- OSV · UbuntuEcosystem advisory · calculated9.3CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber
- OSV · WolfiEcosystem advisory · calculated9.3CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber
- OSV · ChainguardEcosystem advisory · calculated9.3CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber
- NVDNIST9.3CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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
Critical 9.1Preferred score · OSV · Ubuntu (Ecosystem advisory) · calculated from vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NSourcesAll 3 agree
- OSV · DebianEcosystem advisory · calculated9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- NVDNIST9.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.34%
Chance of exploitation in the next 30 days
Percentile
26%
Versus all other CVEs
30-day change
+0.07 pp
From 0.27% on 19-09-2026
19-09-202619-10-2026
EPSS score0.34%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Chainguard4 products
- keycloak-26.6< 26.6.7-r1
- keycloak-26.6-iamguarded-compat< 26.6.7-r1
- keycloak-26.7< 26.7.4-r1
- keycloak-26.7-iamguarded-compat< 26.7.4-r1
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
Wolfi2 products
- keycloak-26.6< 26.6.7-r1
- keycloak-26.6-iamguarded-compat< 26.6.7-r1
Debian1 product
- bouncycastleAll versions (No fix recorded) | < 1.86-1
Ubuntu1 product
- bouncycastleAll versions (No fix recorded)
6 vendors · 12 products
References
11 links- github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059650Vendor AdvisoryREPORTAdvisoryThird Party Advisory
- github.com/bcgit/bc-javaPACKAGE
Show all 11 references
- github.com/bcgit/bc-lts-javaPACKAGE