SB20261021101 - Information Exposure Through Timing Discrepancy in Bouncy Castle for Java

Description

This security bulletin contains information about 1 vulnerability.

1) Information Exposure Through Timing Discrepancy (CVE-ID: CVE-2026-18036)

CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to recover information about NTRU private key material through timing measurements.

The vulnerability exists due to observable timing discrepancies in the mod3 and modQ reduction helpers in org.bouncycastle.pqc.math.ntru.Polynomial and org.bouncycastle.pqc.crypto.ntru.NTRUSampling when performing secret-dependent modular reductions during key generation, encapsulation, and decapsulation. A remote attacker can measure and analyze the latency of these operations to infer information about NTRU private key material.

Remediation

Install update from vendor's website.

References

• https://security.snyk.io/vuln/SNYK-JAVA-ORGBOUNCYCASTLE-20419431
• https://github.com/bcgit/bc-java/commit/9c9ad88b6003bb6230d2434bd892cc1e95b294e4
• https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9018036