Vulnerability in LibreChat (CVE-2026-54027)
Summary
Vulnerability in LibreChat (CVE-2026-54027). Data can be tampered with by attackers. Exploitable via POST /api/files/images. Mitigation: upgrade to 0.8.4-rc1 or later.
Original description
The description as published by the source.
LibreChat is an enhanced ChatGPT clone that supports multiple AI providers. Prior to 0.8.4-rc1, the POST /api/files/images endpoint allows any authenticated user to upload files into any agent's tool_resources (e.g., context, execute_code) without verifying ownership or EDIT permission on the target agent. A permission check was added to the POST /api/files route in a previous patch, but the image upload route was never updated with the same check. An attacker can simply use the image endpoint instead of the file endpoint to bypass the authorization entirely. This vulnerability is fixed in 0.8.4-rc1.
Source: NIST National Vulnerability Database NVD
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-2026-54027 has been found in LibreChat.
Attackers can target a specific entry point like POST /api/files/images over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 6.5/10.
What to do: upgrade LibreChat to 0.8.4-rc1 or later.
If unsure, ask your IT team or search "LibreChat CVE-2026-54027" on the vendor's site.
CVE-2026-54027 (LibreChat) — CWE-862 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/files/images / POST /api/files
Patched: 0.8.4-rc1 — 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.
A vulnerability (CWE-862) exists in LibreChat. Attackers reach the vulnerable code path via POST /api/files/images.
Check the vendor advisory for the affected versions of LibreChat. Attack surface: POST /api/files/images / POST /api/files.
Severity: Medium (CVSS 6.5/10). Data can be tampered with by attackers.
Update to 0.8.4-rc1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /api/files/images requests with malformed payloads or SQL meta-characters. Run grep -r 'LibreChat' . 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 'LibreChat' . | 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
LibreChatを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /api/files/images' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/files/imagesへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade LibreChat to 0.8.4-rc1ステージング環境で 0.8.4-rc1 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と、Step 2 で見つけた異常検知の続報チェックを含めること。
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4Post-deployment verification verify
Replay attack against POST /api/files/images on staging to confirm patch closes the vector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 Step 2 と同じログクエリでアラート再発が無いか継続監視。
References
- exploit github.com