Bouncy Castle is a widely used Java cryptography library across enterprise software; a DoS through quadratic-time DN stringification can disrupt authentication/TLS and many services.
CVE-2026-58059
Quadratic-time X.500 DN stringification in Bouncy Castle enables CPU DoS.
Is CVE-2026-58059 being exploited?
Not confirmed. CVE-2026-58059 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 0.52% probability of exploitation in the next 30 days.
How severe is CVE-2026-58059?
CVE-2026-58059 is rated High with a CVSS score of 8.7. 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-2026-58059?
Yes. A fix has been recorded for CVE-2026-58059. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-58059 affect?
CVE-2026-58059 affects Bouncy Castle for Java < 1.85, Bouncy Castle for Java LTS < 2.73.12, BC-FJA (bc-fips) < 1.0.2.7 (1.0.x series), BC-FJA (bc-fips) < 2.0.2 (2.0.x series), and 1 further product or version. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-58059?
Upgrade to fixed Bouncy Castle versions (>=1.85, >=2.73.12, bc-fips >=1.0.2.7/2.0.2/2.1.3).
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Algorithmic complexity vulnerability allows remote attacker to cause high CPU usage and service denial by supplying malicious X.500 distinguished names during DN stringification.
Patch when possible
- affected>= 1.0.0 and < 1.0.2.7
- affected>= 2.0.0 and < 2.0.2
- affected>= 2.1.0 and < 2.1.3
- affected< 1.85
- affected>= 2.73.0 and < 2.73.12
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.