Vulnerability · CVE-2026-97370

Junrar is an open source Java RAR archive library.

Published Oct 15, 2026 · corrected/updated Oct 15, 2026 · junrar junrar · evidence confidence high

### 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.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2026-97370 is a high public vulnerability record for junrar junrar. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether junrar junrar is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: com.github.junrar:junrar (0 → 7.6.1); com.github.junrar; junrar junrar. Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 7.5. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-835. Sources contributing to this record: cve_org, github, gitlab, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

Exploitation evidence
Not listed as known exploited in CISA KEV. Not in CISA KEV or VulnCheck KEV.
Patch and remediation
No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.
Safe detection guidance
Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

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
maven com.github.junrarversion unspecified
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
GitLab Advisory DatabasePackage advisoryCVE-2026-97370
Junrar's RAR virtual machine can be forced into a deterministic infinite loop while extracting a crafted RAR4 archive. The RarVM.ExecuteCode loop is intended to be bounded by maxOpCount, but jump instructions can bypass this limit when setIP() is called with a target instruction pointer greater than or equal to codeSize. An unauthenticated attacker who can provide a RAR archive to an application u
advisories.gitlab.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
OpenSSF OSV / OSV ScannerPackage advisoryGHSA-h9h9-2rmf-rvhp
Junrar: RarVM VM_JMP maxOpCount bypass causes infinite CPU loop during RAR4 extraction
osv.dev