CVE-2026-19670Public exploitNetwork attack vector

Admin-path access via percent-encoded URI

Published Aug 18, 2026 · Updated Aug 18, 2026

Incorrect authorization in Malcolm before 26.08.0 allows remote authenticated users to reach admin-only paths via percent-encoded URLs. In nginx/lua/nginx_auth_helpers.lua, check_rbac() matches role rules against ngx.var.request_uri after only collapsing literal /../ segments, so normalize_uri_for_rbac() never percent-decodes the path before the access check. Any low-privilege account that depends on Malcolm's proxy-layer RBAC can request paths such as /%68tadmin.php and be routed by nginx to protected backends that the literal /htadmin.php path would block.

CVSS severity5.4
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Malcolm before 26.08.0 allows remote authenticated users to reach admin-only paths via percent-encoded URLs. In nginx/lua/nginx_auth_helpers.lua, check_rbac() matches role rules against ngx.var.request_uri after only collapsing literal /../ segments, so normalize_uri_for_rbac() never percent-decodes the path before the access check. Any low-privilege account that depends on Malcolm's proxy-layer RBAC can request paths such as /%68tadmin.php and be routed by nginx to protected backends that the literal /htadmin.php path would block.

The record

CVE
CVE-2026-19670
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Cybersecurity and Infrastructure Security Agency (CISA)
Product
Malcolm
Classifications
CWE-863, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=26.07.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Cybersecurity and Infrastructure Security Agency (CISA) · Malcolmversion=0 <=26.07.1

Published CVSS scores

5.3CVE Program via OSVCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
5.4cisagov/Malcolm GitHub AdvisoryCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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