CVE-2021-30477
Estado: ModificadaMedia (4.3)—
An issue was discovered in Zulip Server before 3.4. A bug in the implementation of replies to messages sent by outgoing webhooks to private streams meant that an outgoing webhook bot could be used to send messages to private streams that the user was not intended to be able to send messages to.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- Puntuación base: 4.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.66%
- Percentil entre todas las CVEs puntuadas: 50
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- NVD-CWE-noinfo
Referencias
JSON original (NVD)
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{
"id": "CVE-2021-30477",
"cveTags": [],
"metrics": {
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"source": "nvd@nist.gov",
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"vectorString": "AV:N/AC:L/Au:S/C:N/I:P/A:N",
"authentication": "SINGLE",
"integrityImpact": "PARTIAL",
"accessComplexity": "LOW",
"availabilityImpact": "NONE",
"confidentialityImpact": "NONE"
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"integrityImpact": "LOW",
"userInteraction": "NONE",
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"availabilityImpact": "NONE",
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"affected": [
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"source": "cve@mitre.org",
"affectedData": [
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"published": "2021-04-15T00:15:13.047",
"references": [
{
"url": "https://blog.zulip.com/2021/04/14/zulip-server-3-4/",
"tags": [
"Release Notes",
"Vendor Advisory"
],
"source": "cve@mitre.org"
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{
"url": "https://blog.zulip.com/2021/04/14/zulip-server-3-4/",
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"vulnStatus": "Modified",
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"descriptions": [
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"value": "An issue was discovered in Zulip Server before 3.4. A bug in the implementation of replies to messages sent by outgoing webhooks to private streams meant that an outgoing webhook bot could be used to send messages to private streams that the user was not intended to be able to send messages to."
},
{
"lang": "es",
"value": "Se detectó un problema en Zulip Server versiones anteriores a 3.4. Un bug en la implementación de las respuestas a los mensajes enviados por webhooks salientes a transmisiones privadas significaba que un bot webhook saliente podía usarse para enviar mensajes a transmisiones privadas a las que el usuario no tenía la intención de poder enviar mensajes"
}
],
"lastModified": "2026-06-17T03:50:18.860",
"configurations": [
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