CVE-2026-90852 luben zstd-jni Dictionary Sharing ZstdCompressCtx.java ZstdCompressCtx.loadDict use after free
A use-after-free vulnerability in zstd-jni allows remote attackers to potentially execute code or cause denial of service via dictionary sharing.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90852?
CVE-2026-90852 is a medium-severity use after free vulnerability in luben zstd-jni, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability has been found in luben zstd-jni up to 1.5.7-13. This vulnerability affects the function ZstdCompressCtx.loadDict of the file ZstdCompressCtx.java of the component Dictionary Sharing. Such manipulation leads to use after free. The attack can be executed remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 1.5.7-14 is able to resolve this issue. The name of the patch is a560131d7834598afd9cea6b7c107bc88e915936. The affected component should be upgraded. The vendor was contacted early, responded in a very professional manner and quickly released a fixed version of the affected product.
Which versions are affected by CVE-2026-90852?
How do I fix CVE-2026-90852?
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-2026-90852 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-90852 exists.
Sources
Also known as CLEANSTART-2026-FH00186, CLEANSTART-2026-JE63853, CLEANSTART-2026-SX37401, CLEANSTART-2026-UP93345, CLEANSTART-2026-WG76830, DEBIAN-CVE-2026-90852 and 2 more.