What’s Vulnerable › Vulnerabilities

CVE-2026-116486: Objenesis before 3.6 Type Confusion via Class Name Instantiator Cache

• Severity: medium (CVSS 4.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-26 · updated 2026-10-26
• Weakness: CWE-386

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 products

• easymock objenesis: before 3.6 — fixed in 3.6

How to fix

Upgrade to a fixed version: easymock objenesis 3.6. Check the vendor advisory for mitigations.

References

• https://github.com/easymock/objenesis
• https://github.com/easymock/objenesis/blob/fb36e5c377ed1bf57a18386fa79d2eed4ddfcfac/main/src/main/java/org/objenesis/ObjenesisBase.java#L92-L95
• https://github.com/easymock/objenesis/commit/40f90f435a06b16af74a7398f0007faeaa52c00c
• https://github.com/easymock/objenesis/security/advisories/GHSA-743r-26gf-97ff
• https://www.vulncheck.com/advisories/objenesis-before-3.6-type-confusion-via-class-name-instantiator-cache

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