CVE-2026-8763

Status: AnalyzedCritical (9.3)—

In Bouncy Castle for Java before 1.85, Name Constraints bypass via trailing dot in rfc822Name and URI. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 1.0.2.7 (1.0.X series), 2.0.2 (2.0.X series) and 2.1.3 (2.1.X series).

CVSS

Version: 4.0
Vector: 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/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
Base score: 9.3

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.43%
Percentile among all scored CVEs: 35
Score date: 10/4/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access85 %
Primary impactT1557 Adversary-in-the-Middlecredential access · collection80 %
Secondary impactT1212 Exploitation for Credential Accesscredential access75 %

Vulnerabilidad de elusión de Name Constraints en certificados (CWE-295) accesible remotamente sin autenticación (AV:N/PR:N/UI:N). Permite falsificar certificados de dominios confiables, facilitando ataques MITM y compromiso de credenciales en comunicaciones cifradas.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Isolation and Sandboxing Exploit Protection Update Software

Affected technologies (3)

Bouncycastle — Bc-java Bouncycastle — Bouncy Castle FOR Java LTS Bouncycastle — Fips Java API

CWEs

CWE-295

References

Raw JSON (NVD)

Show

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