Authorization Flaw in Malcolm (CVE-2026-63177)
Summary
Vulnerability in Malcolm (CVE-2026-63177). Confidential information can be exposed externally. Exploitable via ngx.var.request_uri.
Original description
The description as published by the source.
Malcolm is a network traffic analysis tool suite. Prior to version 26.07.0, role-based access control enforced in the Nginx OpenResty Lua layer evaluates the raw, unnormalized ngx.var.request_uri, while Nginx itself routes requests using the normalized path. An authenticated low-privilege user can prepend a traversal segment (for example /x/../upload/...) so that Nginx routes the request to a restricted backend while the Lua role check fails to match any rule and falls open, granting access it should deny. Version 26.07.0 fixes the issue.
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-2026-63177 has been found in Malcolm.
Attackers can target a specific entry point like ngx.var.request_uri over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Malcolm CVE-2026-63177" on the vendor's site.
CVE-2026-63177 (Malcolm) — CWE-863 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: ngx.var.request_uri
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.
Incorrect authorization (CWE-863) exists in Malcolm. Attackers reach the vulnerable code path via ngx.var.request_uri.
Check the vendor advisory for the affected versions of Malcolm. Attack surface: ngx.var.request_uri.
Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
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 'Malcolm' . 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
-
1Identify exposure identify
grep -r 'Malcolm' . | 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
Malcolmを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-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。
References
- web ics-cert@hq.dhs.gov
- web ics-cert@hq.dhs.gov
- web ics-cert@hq.dhs.gov
- web ics-cert@hq.dhs.gov