Description
Memos' webhook URL validation, isReservedIP() (internal/webhook/validate.go), checks a candidate IP against a reservedCIDRs list that omits 0.0.0.0/8 and never calls ip.IsUnspecified() — unlike the correctly implemented sibling function isInternalIP() in internal/httpgetter/html_meta.go, which does. Because Linux redirects connections to 0.0.0.0 to loopback (127.0.0.1), an attacker registering a webhook URL of http://0.0.0.0:PORT/ bypasses the reserved-IP check and causes the Memos server to make outbound HTTP requests to its own loopback interface, exposing internal-only services.
Published: 2026-08-05
Score: 8.5 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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History

Wed, 05 Aug 2026 15:00:00 +0000

Type Values Removed Values Added
First Time appeared Usememos
Usememos memos
Vendors & Products Usememos
Usememos memos

Wed, 05 Aug 2026 13:15:00 +0000

Type Values Removed Values Added
Description Memos' webhook URL validation, isReservedIP() (internal/webhook/validate.go), checks a candidate IP against a reservedCIDRs list that omits 0.0.0.0/8 and never calls ip.IsUnspecified() — unlike the correctly implemented sibling function isInternalIP() in internal/httpgetter/html_meta.go, which does. Because Linux redirects connections to 0.0.0.0 to loopback (127.0.0.1), an attacker registering a webhook URL of http://0.0.0.0:PORT/ bypasses the reserved-IP check and causes the Memos server to make outbound HTTP requests to its own loopback interface, exposing internal-only services.
Title Memos Webhook SSRF via 0.0.0.0 Reserved-IP Bypass
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 8.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N'}

Subscriptions

Usememos Memos
cve-icon MITRE

Status: PUBLISHED

Assigner: TuranSec

Published:

Updated: 2026-08-05T12:26:18.502Z

Reserved: 2026-08-05T12:23:34.967Z

Link: CVE-2026-71271

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-05T15:00:05Z

Weaknesses
  • CWE-918

    Server-Side Request Forgery (SSRF)