What is CVE-2017-13098?

CVE-2017-13098 is a high-severity vulnerability in Bouncycastle Bc-Java, classified under Observable Discrepancy. CVSS score: 7.5/10. Published 2017-12-13.

How severe is CVE-2017-13098?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2017-13098 known to be exploited?

12 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Bouncycastle Bc-Java

CVE-2017-13098

BouncyCastle TLS prior to version 1.0.3, when configured to use the JCE (Java Cryptography Extension) for cryptographic functions, provides a weak Bleichenbacher oracle when any TLS cipher suite using RSA key exchange is negotiated. An attacker can recover the private key from a vulnerable application. This vulnerability is referred to as "ROBOT."

Published 2017-12-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.243 (97.8th percentile), scored 2026-09-29.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 98th percentile — 97.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.243 · newest: 0.243 · change: 0.000

Affected products

Bouncycastle Bc-Java
Legion Of The Bouncy Castle Bouncycastle TLS — versions <1.0.3

Weakness classification (CWE)

CWE-203 — Observable Discrepancy

Public proof-of-concept exploits

References

www.securityfocus.com/bid/102195 (VDB Entry, Third Party Advisory, vdb-entry)
www.kb.cert.org/vuls/id/144389 (US Government Resource, Third Party Advisory, Mitigation, Issue Tracking, third-party-advisory)
www.debian.org/security/2017/dsa-4072 (vendor-advisory, Third Party Advisory, Issue Tracking)
lists.opensuse.org/opensuse-security-announce/2020-05/msg00011.html (vendor-advisory)
www.oracle.com/security-alerts/cpuoct2020.html
robotattack.org/ (Third Party Advisory, Issue Tracking)
github.com/bcgit/bc-java/commit/a00b684465b38d722ca9a3543b8af8568e6bad5c (Patch, Third Party Advisory, Issue Tracking)
security.netapp.com/advisory/ntap-20171222-0001/ (Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2017-13098?: CVE-2017-13098 is a high-severity vulnerability in Bouncycastle Bc-Java, classified under Observable Discrepancy. CVSS score: 7.5/10. Published 2017-12-13.
How severe is CVE-2017-13098?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2017-13098 known to be exploited?: 12 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.