Path Traversal in com.github.jknack:handlebars-springmvc (CVE-2026-63490)
Summary
Path traversal in com.github.jknack:handlebars-springmvc (CVE-2026-63490). Confidential information can be exposed externally. Exploitable via ResourceLoader. Mitigation: upgrade to 4.5.3 or later.
Original description
The description as published by the source.
Summary
com.github.jknack.handlebars.springmvc.SpringTemplateLoader resolves Spring MVC view names into URLs via Spring's ResourceLoader without applying the path-containment check that protects every other URL-based loader in the project (ClassPathTemplateLoader, FileTemplateLoader, ServletContextTemplateLoader - all hardened by commit d177cdee).
The only remaining defense for file: / classpath: view names is the unconditional .hbs suffix appended by AbstractTemplateLoader.resolve(...). This suffix is the load-bearing security boundary that prevents a request like view=file:/etc/passwd from reading /etc/passwd instead of /etc/passwd.hbs.
This boundary is bypassed by a single character: # (the URL fragment delimiter).
When the view name ends with #, the appended .hbs lands inside the URL fragment. Both Spring's FileUrlResource.exists() (via URI.getSchemeSpecificPart()) and the JDK's URL.openStream() (via URL.getFile()) silently discard the fragment, so the file actually opened is the bare path the attacker specified - for example /etc/passwd rather than /etc/passwd.hbs. The compiled "template" is then parsed and rendered into the HTTP response body.
Result: unauthenticated, network-reachable, arbitrary file read of any file readable by the JVM process on any Spring MVC application that uses a default-configured HandlebarsViewResolver and exposes a controller that returns a (fully or partly) user-influenced…
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-2026-63490 has been found in com.github.jknack:handlebars-springmvc.
Attackers can target a specific entry point like ResourceLoader over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade com.github.jknack:handlebars-springmvc to 4.5.3 or later.
If unsure, ask your IT team or search "com.github.jknack:handlebars-springmvc CVE-2026-63490" on the vendor's site.
CVE-2026-63490 (com.github.jknack:handlebars-springmvc) — CWE-22 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: ResourceLoader / ClassPathTemplateLoader / FileTemplateLoader / ServletContextTemplateLoader
Patched: 4.5.3 — 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.jknack:handlebars-springmvc. Attackers reach the vulnerable code path via ResourceLoader without authentication.
Check the vendor advisory for the affected versions of com.github.jknack:handlebars-springmvc. Attack surface: ResourceLoader / ClassPathTemplateLoader / FileTemplateLoader / ServletContextTemplateLoader.
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.
Update to 4.5.3.
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
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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.jknack:handlebars-springmvc を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade com.github.jknack:handlebars-springmvc to 4.5.3ステージング環境で 4.5.3 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。
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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
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com