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.
Analysis and contextual insights are available on OpenCVE Cloud.
Remediation
No vendor fix or workaround currently provided.
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Tracking
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Advisories
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References
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
|
Status: PUBLISHED
Assigner: TuranSec
Published:
Updated: 2026-08-05T12:26:18.502Z
Reserved: 2026-08-05T12:23:34.967Z
Link: CVE-2026-71271
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OpenCVE Enrichment
Updated: 2026-08-05T15:00:05Z
Weaknesses