CVE-2026-110258: OW2 ASM 3.0 before 9.11 Excessive Memory Allocation via Multiple RET Instructions

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-14 · updated 2026-10-14
Weakness: CWE-789

Description

OW2 ASM 3.0 before 9.11 contains an excessive memory allocation vulnerability in Label.addSubroutineRetSuccessors() that fails to enforce the single-RET-per-JSR rule. Attackers can supply a crafted invalid class file with multiple RET instructions for one JSR, triggering a roughly 2 GB allocation that crashes the JVM.

Affected products

OW2 ASM: from 3.0 before 9.11 — fixed in 9.11

How to fix

Upgrade to a fixed version: OW2 ASM 9.11. Check the vendor advisory for mitigations.

References

https://asm.ow2.io/versions.html
https://gitlab.ow2.org/asm/asm/-/blob/ASM_9_10_1/asm/src/main/java/org/objectweb/asm/Label.java#L568
https://gitlab.ow2.org/asm/asm/-/commit/4dabfe0aef14f8cccb0617640a4add8fbcc4ed36
https://gitlab.ow2.org/asm/asm/-/merge_requests/458
https://www.vulncheck.com/advisories/ow2-asm-3.0-before-9.11-excessive-memory-allocation-via-multiple-ret-instructions

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