Vulnerability · Published Oct 26, 2026 · Assigned by VulnCheck
CVE-2026-116486Objenesis before 3.6 Type Confusion via Class Name Instantiator Cache
Medium 4.5
In plain English
A medium-severity security flaw in objenesis from easymock. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Objenesis before 3.6 contains a type confusion vulnerability that allows code in one class loader to substitute objects into another by exploiting instantiator caching keyed on class name. When a shared ObjenesisStd instance caches instantiators by clazz.getName() in ObjenesisBase.getInstantiatorOf(), same-named classes collide, causing newInstance() to return wrong-class objects and ClassCastException failures.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | objenesis | no fix listed | DEBIAN-CVE-2026-116486 |
| Debian:13 | objenesis | no fix listed | DEBIAN-CVE-2026-116486 |
| Debian:14 | objenesis | 3.6-1 | DEBIAN-CVE-2026-116486 |
| Ubuntu:22.04:LTS | objenesis | no fix listed | UBUNTU-CVE-2026-116486 |
| Ubuntu:24.04:LTS | objenesis | no fix listed | UBUNTU-CVE-2026-116486 |
| Ubuntu:26.04:LTS | objenesis | no fix listed | UBUNTU-CVE-2026-116486 |
| Ubuntu:26.10 | objenesis | no fix listed | UBUNTU-CVE-2026-116486 |
Affected products (as reported)
Weakness: CWE-386 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
References
- Patch Commit patch
- GitHub Security Advisory (GHSA-743r-26gf-97ff) vendor-advisory
- https://github.com/easymock/objenesis/blob/fb36e5c377ed1bf57a18386fa79d2eed4ddfcfac/main/src/main/java/org/objenesis/ObjenesisBase.java#L92-L95 technical-description
- https://github.com/easymock/objenesis product
- VulnCheck Advisory: Objenesis before 3.6 Type Confusion via Class Name Instantiator Cache third-party-advisory