CVE-2026-97370

Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction

Published Oct 15, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Junrar is an open source Java RAR archive library. Prior to 7.6.1, RarVM.ExecuteCode in src/main/java/com/github/junrar/unpack/vm/RarVM.java can repeatedly execute a VM_JMP instruction whose target is greater than or equal to the prepared program's codeSize. The setIP() function returns success without changing the instruction pointer or decrementing maxOpCount, and the jump handler continues before loop-end accounting, leaving both values unchanged. A crafted RAR4 archive can therefore keep an extraction thread in an infinite CPU loop and exhaust archive-processing worker capacity. The RAR virtual machine does not expose native process execution, so the supported impact is availability loss rather than code execution. This issue is fixed in version 7.6.1.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-h9h9-2rmf-rvhp Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction
History
Type Values Removed Values Added
First Time appeared Junrar
Junrar junrar
Vendors & Products Junrar
Junrar junrar
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Junrar is an open source Java RAR archive library. Prior to 7.6.1, RarVM.ExecuteCode in src/main/java/com/github/junrar/unpack/vm/RarVM.java can repeatedly execute a VM_JMP instruction whose target is greater than or equal to the prepared program's codeSize. The setIP() function returns success without changing the instruction pointer or decrementing maxOpCount, and the jump handler continues before loop-end accounting, leaving both values unchanged. A crafted RAR4 archive can therefore keep an extraction thread in an infinite CPU loop and exhaust archive-processing worker capacity. The RAR virtual machine does not expose native process execution, so the supported impact is availability loss rather than code execution. This issue is fixed in version 7.6.1.
Title Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction
Weaknesses CWE-835
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 16, 2026, 5:12 PM
Reserved
Sep 24, 2026, 2:16 PM
Status
Deferred
Published
Oct 15, 2026, 7:17 PM
Modified
Oct 16, 2026, 8:04 PM