CVE-2026-97370 Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction
A crafted RAR4 archive causes an infinite CPU loop in the Junrar library during extraction, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97370?
CVE-2026-97370 is a high-severity denial of service vulnerability in junrar, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-835
Which versions are affected by CVE-2026-97370?
2 open source packages ship an affected version, including com.github.junrar:junrar.
| Package | Affected | Fixed in |
|---|---|---|
com.github.junrar:junrar Maven | All versions | 7.6.1 |
com.github.junrar:junrar Maven | All versions | 7.6.1 |
How do I fix CVE-2026-97370?
Upgrade com.github.junrar:junrar to 7.6.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-97370 being exploited?
There is no known exploitation of CVE-2026-97370 in the wild and no public exploit code.
Sources
Also known as ECHO-f3d7-a91d-ed23, GHSA-h9h9-2rmf-rvhp.