CVE-2026-87825 zstd-jni 1.3.8-4 through 1.5.7-13 Use-After-Free of Compression and Decompression Dictionaries
Attackers can trigger use-after-free in zstd-jni by closing dictionaries prematurely, causing JVM crashes or data corruption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-87825?
CVE-2026-87825 is a high-severity use after free vulnerability in luben zstd-jni, published on 9 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
zstd-jni before 1.5.7-14 contains a use-after-free vulnerability where streams and contexts hold a dictionary's shared lock only during the load call, allowing the dictionary to be closed while still referenced. Attackers can close a dictionary after associating it with a stream or context, causing subsequent read or write operations to access freed native memory, resulting in silent data corruption or JVM crashes.
Weakness: CWE-416
Which versions are affected by CVE-2026-87825?
How do I fix CVE-2026-87825?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-87825 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-87825 exists.
Sources
Also known as CLEANSTART-2026-BS35742, CLEANSTART-2026-II74708, CLEANSTART-2026-MU11707, CLEANSTART-2026-QC84579, CLEANSTART-2026-RT42031, CLEANSTART-2026-YX63078 and 4 more.