Affects widely used BC-JAVA cryptography core; timing side-channel could leak FrodoKEM private keys across Java crypto stacks.
CVE-2026-5598
Timing side-channel in BC-JAVA core risks private key leakage in FrodoKEM.
Is CVE-2026-5598 being exploited?
Not confirmed. CVE-2026-5598 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.90% probability of exploitation in the next 30 days.
How severe is CVE-2026-5598?
CVE-2026-5598 is rated Critical with a CVSS score of 10.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-5598?
Yes. A fix has been recorded for CVE-2026-5598. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-5598 affect?
CVE-2026-5598 affects BC-JAVA core library (Bouncy Castle), FrodoKEM implementations using BC-JAVA. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-5598?
Upgrade BC-JAVA to 1.84+ or apply vendor patch
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Timing-based leakage could enable private key recovery during FrodoKEM operations via observed timing.
Immediate action required
- affected>= 1.71 and < 1.80.2
- affected>= 1.81 and < 1.81.1
- affected>= 1.82 and < 1.84
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.