CVE-2026-71271
Memos Webhook SSRF via 0.0.0.0 Reserved-IP Bypass
CVE-2026-71271 is a high vulnerability (CVSS 8.5) in Usememos Memos, published August 5, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.33%, the 26th percentile. No source names a fixed version.
- Severity
- 8.5 HighCVSS 3.1, CVE List
- Exploit chance
- 0.33%EPSS, 26th percentile
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
- No fix listedNo source names one
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
Exploit likelihood
Affected products
What each source reports
CVE List Score used
Memos Webhook SSRF via 0.0.0.0 Reserved-IP Bypass
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.
- Record
CVE-2026-71271- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
EUVDEUVD-2026-53356
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.
- Record
EUVD-2026-53356- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-jjh5-p3gc-84xr
Memos' webhook URL validation, isReservedIP() (internal/webhook/validate.go), checks a candidate...
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.
- Record
GHSA-jjh5-p3gc-84xr- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-71271- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
OSV
Memos Webhook SSRF via 0.0.0.0 Reserved-IP Bypass
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.
- Record
CVE-2026-71271- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.