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CVE-2026-97370— Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction

Quick assessment

Affected
junrar junrar
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Junrar 是一个开源的 Java RAR 归档库。在 7.6.1 版本之前，RarVM.ExecuteCode（位于 src/main/java/com/github/junrar/unpack/vm/RarVM.java 中）存在一个漏洞：它可以反复执行一条 VM_JMP 指令，其目标地址大于或等于预准备程序代码大小（codeSize）。由于 setIP() 函数在未修改指令指针或未递减 maxOpCount 的情况下仍返回成功，且跳转处理程序在循环结束前的计数检查之前就已执行，导致这两个值保持不变。因此，构

CVSS 7.5 · High EPSS 0.40% · P33

Possible ATT&CK Techniques 1 AI

T1496 · Resource Hijacking

Affected Version Matrix 1

VendorProduct Version RangeStatus
junrar junrar < 7.6.1 affected
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I. Basic Information for CVE-2026-97370

Vulnerability Information
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Vulnerability Title
Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
不可达退出条件的循环(无限循环)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
junrar junrar < 7.6.1 -

II. Public POCs for CVE-2026-97370

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III. Intelligence Information for CVE-2026-97370

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Patches & Fixes for CVE-2026-97370 (1)

Vendor Advisories for CVE-2026-97370 (1)

Other References for CVE-2026-97370 (1)

IV. Related Vulnerabilities

Same product: junrar
Same vendor: junrar
Same weakness: CWE-835

V. Comments for CVE-2026-97370

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