CVE-2026-59649 OpenPGP user-attribute subpacket length bounded only by JVM max memory
Attackers can cause denial of service by crafting OpenPGP user-attribute subpackets with excessive lengths, exhausting JVM memory in Bouncy Castle for Java.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-59649?
CVE-2026-59649 is a high-severity denial of service vulnerability in Bouncycastle Bc-Java, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In Bouncy Castle for Java before 1.85, OpenPGP user-attribute subpacket length bounded only by JVM max memory. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpg-fips 1.0.13 (1.0.X series), 2.0.13 (2.0.X series) and 2.1.13 (2.1.X series).
Weakness: CWE-789
Which versions are affected by CVE-2026-59649?
It affects 3 products.
Products include Bouncycastle Bc-Java, Bouncycastle Bcpg-Fips, Bouncycastle Bouncy Castle for Java Lts.
How do I fix CVE-2026-59649?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-59649 being exploited?
There is no known exploitation of CVE-2026-59649 in the wild and no public exploit code.
Other vulnerabilities in Bouncycastle Bc-Java
- CVE-2007-6721 Legion of the Bouncy Castle Java Cryptography API Bleichenbacher Oracle Vulnerability
- CVE-2018-1000613 Deserialization of Untrusted Data in Bouncy castle
- CVE-2026-58062 Stapled OCSP response accepted without binding to the checked certificate
- CVE-2026-59638 JSSE hostname verifier CN-fallback enabled by default despite documented opt-in
- CVE-2026-59650 MTI/A0 DH agreement exponentiates unvalidated peer value
Sources
Also known as CLEANSTART-2026-PX75697, CLEANSTART-2026-YI46712, CLEANSTART-2026-ZK50778, DEBIAN-CVE-2026-59649, GHSA-r7h8-35pv-fwgx, UBUNTU-CVE-2026-59649.