Path Traversal in craftcms/cms (CVE-2026-72783)
Summary
Path traversal in craftcms/cms (CVE-2026-72783). Confidential information can be exposed externally. Exploitable via ensurePathIsContained. Mitigation: upgrade to 4.18.2 or later.
Original description
The description as published by the source.
The ensurePathIsContained function of the Local file system class is theoretically vulnerable to path traversal, although no exploitable scenario has been discovered.
When a file is read, an Asset object uses the getFileStream method of the Volume where the asset file is stored, which in turn uses the getFileStream method of the file system class used by that Volume. For the Local file system, this function returns a stream to a file on the local disk after verifying and creating the correct file path.
The file path is constructed by first validating the path and then adding a prefix to the validated and normalized path. The prefix is the path to the local directory that houses the particular volume. The order of operations matters here: first, a validation step, afterward a normalization step, and finally the construction of the resulting file path. This opens the possibility of a desanitization-style vulnerability, where the normalization invalidates the assumptions made by the validation or sanitization that preceded it.
Impact
The issue is not directly exploitable, but for hardening, a fix is recommended regardless.
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-2026-72783 has been found in craftcms/cms.
Attackers can target a specific entry point like ensurePathIsContained over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 6.2/10.
What to do: upgrade craftcms/cms to 4.18.2 or later.
If unsure, ask your IT team or search "craftcms/cms CVE-2026-72783" on the vendor's site.
CVE-2026-72783 (craftcms/cms) — CWE-22 / CVSS v3 6.2
Attack vector: local / unauthenticated / no user interaction
Attack surface: ensurePathIsContained / Local / Asset / getFileStream
Patched: 4.18.2 — 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 craftcms/cms. Attackers reach the vulnerable code path via ensurePathIsContained without authentication.
Check the vendor advisory for the affected versions of craftcms/cms. Attack surface: ensurePathIsContained / Local / Asset / getFileStream.
Severity: Medium (CVSS 6.2/10). Confidential information can be exposed externally.
Update to 4.18.2.
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. Run grep -r 'craftcms/cms' . against your dependency files (package-lock.json, requirements.txt, go.sum) 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
grep -r 'craftcms/cms' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
craftcms/cmsを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade craftcms/cms to 4.18.2ステージング環境で 4.18.2 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 vulncheck.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com