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TI-2026-45083 Aliases CVE-2026-63177

Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC

Priority LOW 31CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00369 30th percentileScored 2026-11-07
Fix Fixed Malcolm (cisagov): 26.07.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
cisagovMalcolmbefore 26.07.026.07.0Patch availableCNA
  • Malcolm Vendorcisagov Affected before 26.07.0 Fixed in 26.07.0 Patch available CNA

Remediation

  • Fix · CNA Malcolm (cisagov) Fixed in 26.07.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-63177

References

Other 4

  • TI-2026-45069 Malcolm has Uncontrolled Resource Consumption in Archive Extraction (Inode-Exhaustion DoS) CVSS 4.0HIGH 7.1
  • TI-2026-15970 Improper handling of highly compressed data (data amplification) in CISA Malcolm CVSS 4.0HIGH 7.1
  • TI-2026-45070 Malcolm's Path Traversal in Archive Extraction Allows Arbitrary Directory Creation CVSS 4.0MEDIUM 5.3
  • TI-2026-15969 Incorrect Authorization in CISA Malcolm CVSS 4.0MEDIUM 5.3
  • TI-2026-40197 Malcolm vulnerable to RCE via unrestricted .php upload to the file-upload component CVSS 4.0HIGH 8.7

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences