CVE-2026-97370

Junrar is an open source Java RAR archive library.

Published Oct 15, 2026 · updated Oct 15, 2026 · junrar junrar

### Summary Junrar's RAR virtual machine can be forced into a deterministic infinite loop while extracting a crafted RAR4 archive. The loop is intended to be bounded by , but jump instructions can bypass this limit when is called with a target instruction pointer greater than or equal to . An unauthenticated attacker who can provide a RAR archive to an application using can cause the extraction thread to spin forever, consuming CPU and blocking the process. The issue is a denial of service vulnerability, not remote code execution. ### Details The root cause is in . returns early when the target IP is outside the prepared VM program: When , this branch: - does not update ; - does not decrement ; - returns , so callers treat it as success. The handler and the other jump-like handlers discard the return value of and immediately the main VM loop: Because of the , execution also skips the loop-end accounting: As a result, a VM program containing a single instruction can freeze both and : 1. points to the instruction. 2. The jump target resolves to or larger. 3. returns before modifying or decrementing . 4. The caller ignores the return value and continues. 5. The same instruction is executed again forever. ### Impact This is a CPU denial of service vulnerability. Any application that uses junrar to extract untrusted RAR archives can have an extraction worker thread permanently blocked by a small crafted archive. In services that process uploads or attachments automatically, repeated submissions can exhaust worker capacity and degrade or stop archive-processing functionality. The RAR VM does not provide native code execution, reflection, or process execution primitives, and Java array bounds checks prevent escaping the VM memory array. The expected security impact is availability only.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

Oct 15, 2026 · NIST NVD
Detected
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 befo
Oct 15, 2026 · GitHub Advisory Database
Fix available
com.github.junrar:junrar fixed in 7.6.1
Oct 15, 2026 · GitHub Advisory Database
Fix available
com.github.junrar:junrar fixed in 7.6.1
Oct 15, 2026 · GitHub Advisory Database
Updated
### Summary Junrar's RAR virtual machine can be forced into a deterministic infinite loop while extracting a crafted RAR4 archive. The loop is intended to be bounded by , but jump instructions can bypass this limit when is called with a target instruction pointer greater than or equal to . An unauthenticated attacker who can provide a RAR archive to an application using can cause the extraction th

Affected

Maven com.github.junrar:junrar0 → 7.6.1
vendor junrar junrarversion unspecified

Sources

CVE.orgVulnerability recordCVE-2026-97370
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
cve.org
GitHub Advisory DatabasePackage advisoryGHSA-h9h9-2rmf-rvhp
GitHub Advisory Database record mirrored by OSV.
github.com
NIST NVDVulnerability recordCVE-2026-97370
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
nvd.nist.gov
OSV.devPackage advisoryGHSA-h9h9-2rmf-rvhp
Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction
osv.dev