Quick answers
- Is CVE-2026-87823 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-87823 being exploited in the wild.
- How severe is CVE-2026-87823?
- High severity, with a CVSS score of 8.2, published 9 September 2026.
- Which products and versions are affected?
- Luben Zstd-Jni before 1.5.7-14.
- Is there a fix for CVE-2026-87823?
- A patch was published on 2026-08-16: Version 1.5.7-14 released with fix Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-87823 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-87823?
- Check whether you run Luben Zstd-Jni at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability exists in three native methods that process direct-ByteBuffer frame sizes, which use 32-bit signed integer bounds checks. An attacker can supply offset values near Integer.MIN_VALUE to bypass these checks, triggering out-of-bounds memory reads via integer overflow. The methods are network-reachable if zstd-jni is used to decompress untrusted data. Successful exploitation results in JVM termination or extraction of arbitrary frame size data from unintended memory locations. Affected versions are before 1.5.7-14; the fix corrects the bounds validation logic.
Affected products
- Luben zstd-jni before 1.5.7-14
Timeline
- 2026-09-09: disclosed
- 2026-08-16: patched: Version 1.5.7-14 released with fix