CVE-2026-71271

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.

CVSS v3 8.5 HIGH

8.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.1 / Impact : 4.7

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact LOW

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/usememos/memos
https://github.com/usememos/memos/blob/main/internal/webhook/validate.go

Configurations

No configuration.

History

23 Oct 2026, 21:10

Type	Values Removed	Values Added
Summary		(es) La validación de URL de webhook de Memos, isReservedIP() (internal/webhook/validate.go), comprueba una IP candidata contra una lista de reservedCIDRs que omite 0.0.0.0/8 y nunca llama a ip.IsUnspecified() - a diferencia de la función hermana correctamente implementada isInternalIP() en internal/httpgetter/html_meta.go, que sí lo hace. Debido a que Linux redirige las conexiones a 0.0.0.0 a loopback (127.0.0.1), un atacante que registra una URL de webhook de http://0.0.0.0:PORT/ omite la comprobación de IP reservada y hace que el servidor de Memos realice solicitudes HTTP salientes a su propia interfaz de loopback, exponiendo servicios solo internos.

Information

Published : 2026-08-05 13:24

Updated : 2026-10-24 15:10

NVD link : CVE-2026-71271

Mitre link : CVE-2026-71271

CVE.ORG link : CVE-2026-71271

JSON object : View

Products Affected

No product.

CWE

CWE-918

Server-Side Request Forgery (SSRF)

{"id": "CVE-2026-71271", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-71271", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-08-05T15:38:03.435461Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 8.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 4.7, "exploitabilityScore": 3.1}]}, "affected": [{"source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "affectedData": [{"vendor": "usememos", "product": "memos", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThanOrEqual": "0.29.1"}], "programFiles": ["internal/webhook/validate.go"], "defaultStatus": "unaffected"}]}], "published": "2026-08-05T13:24:51.447", "references": [{"url": "https://github.com/usememos/memos", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"}, {"url": "https://github.com/usememos/memos/blob/main/internal/webhook/validate.go", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "description": [{"lang": "en", "value": "CWE-918"}]}], "descriptions": [{"lang": "en", "value": "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 \u2014 unlike the correctly implemented sibling function isInternalIP in internal/httpgetter/html_meta.go, which does."}, {"lang": "es", "value": "La validaci\u00f3n de URL de webhook de Memos, isReservedIP() (internal/webhook/validate.go), comprueba una IP candidata contra una lista de reservedCIDRs que omite 0.0.0.0/8 y nunca llama a ip.IsUnspecified() - a diferencia de la funci\u00f3n hermana correctamente implementada isInternalIP() en internal/httpgetter/html_meta.go, que s\u00ed lo hace. Debido a que Linux redirige las conexiones a 0.0.0.0 a loopback (127.0.0.1), un atacante que registra una URL de webhook de http://0.0.0.0:PORT/ omite la comprobaci\u00f3n de IP reservada y hace que el servidor de Memos realice solicitudes HTTP salientes a su propia interfaz de loopback, exponiendo servicios solo internos."}], "lastModified": "2026-10-24T15:10:00.190", "sourceIdentifier": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"}