Path Traversal in com.github.junrar:junrar (CVE-2026-86071)
Summary
Path traversal in com.github.junrar:junrar (CVE-2026-86071). Risk of unauthorized operations or information disclosure. Exploitable via LocalFolderExtractor. Mitigation: upgrade to 7.6.1 or later.
Original description
The description as published by the source.
Summary
LocalFolderExtractor validates only the final canonical file path before extraction. However, makeFile() creates intermediate directories one path segment at a time without checking whether each created directory remains inside the destination folder.
A malicious RAR entry can make the final file path resolve inside the extraction destination, while causing intermediate mkdir() calls to create attacker-chosen directories outside the extraction root.
This is an extraction root escape via unchecked intermediate directory creation. The default impact is directory creation outside the intended destination, not unconditional arbitrary file content write.
Affected Code
src/main/java/com/github/junrar/LocalFolderExtractor.javacreateFile()checks only the final canonical path.makeFile()callsdir.mkdir()for each intermediate segment without containment checks.
Relevant code flow:
private File createFile(final FileHeader fh, final File destination) throws IOException {
String name = invariantSeparatorsPathString(fh.getFileName());
File f = new File(destination, name);
String dirCanonPath = f.getCanonicalPath();
if (!dirCanonPath.startsWith(destination.getCanonicalPath() + File.separator)) {
throw new IllegalStateException(...);
}
if (!f.exists()) {
f = makeFile(destination, name);
}
return f;
}
private File makeFile(final File destination, final String name) throws IOException {…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-86071 has been found in com.github.junrar:junrar.
Attackers can target a specific entry point like LocalFolderExtractor over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 3.7/10.
What to do: upgrade com.github.junrar:junrar to 7.6.1 or later.
If unsure, ask your IT team or search "com.github.junrar:junrar CVE-2026-86071" on the vendor's site.
CVE-2026-86071 (com.github.junrar:junrar) — CWE-22 / CVSS v3 3.7
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: LocalFolderExtractor
Patched: 7.6.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in com.github.junrar:junrar. Attackers reach the vulnerable code path via LocalFolderExtractor without authentication.
Check the vendor advisory for the affected versions of com.github.junrar:junrar. Attack surface: LocalFolderExtractor.
Severity: Low (CVSS 3.7/10). Risk of unauthorized operations or information disclosure.
Update to 7.6.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで com.github.junrar:junrar を使っているサービスとバージョンを洗い出す。
-
2Apply patch patch
Upgrade com.github.junrar:junrar to 7.6.1ステージング環境で 7.6.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- web github.com
- web github.com
- web github.com
- web nvd.nist.gov
- web github.com