CVE-2026-63177
Malcolm Vulnerable to Authorization Bypass via URI Normalization Differential in Nginx Lua RBAC
Description
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.
INFO
Published Date :
Aug. 11, 2026, 9:17 p.m.
Last Modified :
Oct. 24, 2026, 4:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | MITRE-CVE | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Malcolm to version 26.07.0.
- Apply vendor patches if available.
- Review access control configurations.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-63177.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-63177 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-63177
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-63177 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-63177 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Changed Translation Title: Malcolm de cisagov, Description: Malcolm es una suite de herramientas de análisis de tráfico de red. Antes de la versión 26.07.0, el control de acceso basado en roles implementado en la capa Lua de Nginx OpenResty evalúa la ’ngx.var.request_uri’ sin procesar y sin normalizar, mientras que Nginx en sí mismo enruta las solicitudes utilizando la ruta normalizada. Un usuario autenticado con pocos privilegios puede anteponer un segmento de recorrido (por ejemplo, ’/x/.. / upload/...’) de modo que Nginx enrute la solicitud a un backend restringido mientras que la verificación de rol de Lua no logra coincidir con ninguna regla y queda abierta, otorgando acceso que debería denegar. La versión 26.07.0 corrige el problema. Title: Malcolm de cisagov, Description: Malcolm es una suite de herramientas de análisis de tráfico de red. Antes de la versión 26.07.0, el control de acceso basado en roles implementado en la capa Lua de Nginx OpenResty evalúa la ’ngx.var.request_uri’ sin procesar y sin normalizar, mientras que Nginx en sí mismo enruta las solicitudes utilizando la ruta normalizada. Un usuario autenticado con pocos privilegios puede anteponer un segmento de recorrido (por ejemplo, ’/x/.. / upload/...’) de modo que Nginx enrute la solicitud a un backend restringido mientras que la verificación de rol de Lua no logra coincidir con ninguna regla y queda abierta, otorgando acceso que debería denegar. La versión 26.07.0 corrige el problema. -
CVE Translated by [email protected]
Oct. 23, 2026
Action Type Old Value New Value Added Translation Title: Malcolm de cisagov, Description: Malcolm es una suite de herramientas de análisis de tráfico de red. Antes de la versión 26.07.0, el control de acceso basado en roles implementado en la capa Lua de Nginx OpenResty evalúa la ’ngx.var.request_uri’ sin procesar y sin normalizar, mientras que Nginx en sí mismo enruta las solicitudes utilizando la ruta normalizada. Un usuario autenticado con pocos privilegios puede anteponer un segmento de recorrido (por ejemplo, ’/x/.. / upload/...’) de modo que Nginx enrute la solicitud a un backend restringido mientras que la verificación de rol de Lua no logra coincidir con ninguna regla y queda abierta, otorgando acceso que debería denegar. La versión 26.07.0 corrige el problema. -
CVE Modified by [email protected]
Oct. 02, 2026
Action Type Old Value New Value Changed Description 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. 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Added CWE CWE-863 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/63xxx/CVE-2026-63177.json">CVE-2026-63177</a> Added Reference https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-230-01.json Added Reference https://github.com/cisagov/Malcolm/releases/tag/v26.07.0 Added Reference https://github.com/cisagov/Malcolm/security/advisories/GHSA-m5fr-rv3h-xg2r Added Reference https://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01 -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 12, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-63177', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-08-12T22:07:37.481958Z'} -
New CVE Received by [email protected]
Aug. 11, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'cisagov', 'product': 'Malcolm', 'versions': [{'status': 'affected', 'version': '< 26.07.0'}]}] Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Added CWE CWE-863 Added Reference https://github.com/cisagov/Malcolm/releases/tag/v26.07.0 Added Reference https://github.com/cisagov/Malcolm/security/advisories/GHSA-m5fr-rv3h-xg2r