CVE-2021-28714
Status: ModifiedMedium (6.5)—
Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them.
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There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)
CVSS
- Version: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
- Base score: 6.5
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days: 0.33%
- Percentile among all scored CVEs: 24
- Score date: 10/12/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (2)
CWEs
- CWE-770
References
- https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://www.debian.org/security/2022/dsa-5050
- https://www.debian.org/security/2022/dsa-5096
- https://xenbits.xenproject.org/xsa/advisory-392.txt
- https://lists.debian.org/debian-lts-announce/2022/03/msg00011.html
- https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
- https://www.debian.org/security/2022/dsa-5050
- https://www.debian.org/security/2022/dsa-5096
- https://xenbits.xenproject.org/xsa/advisory-392.txt
Raw JSON (NVD)
Show
{
"id": "CVE-2021-28714",
"cveTags": [],
"metrics": {
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"affected": [
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"affectedData": [
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"published": "2022-01-06T18:15:07.760",
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"description": [
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"value": "Guest can force Linux netback driver to hog large amounts of kernel memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Incoming data packets for a guest in the Linux kernel's netback driver are buffered until the guest is ready to process them. There are some measures taken for avoiding to pile up too much data, but those can be bypassed by the guest: There is a timeout how long the client side of an interface can stop consuming new packets before it is assumed to have stalled, but this timeout is rather long (60 seconds by default). Using a UDP connection on a fast interface can easily accumulate gigabytes of data in that time. (CVE-2021-28715) The timeout could even never trigger if the guest manages to have only one free slot in its RX queue ring page and the next package would require more than one free slot, which may be the case when using GSO, XDP, or software hashing. (CVE-2021-28714)"
},
{
"lang": "es",
"value": "Un huésped puede forzar al controlador de netback de Linux a acaparar grandes cantidades de memoria del kernel E[ste registro de información CNA es relacionado con múltiples CVEs; el texto explica qué aspectos/vulnerabilidades corresponden a cada CVE]. Los paquetes de datos entrantes para un huésped en el controlador de netback del kernel de Linux son almacenados en el búfer hasta que el huésped está listo para procesarlos. Son tomadas algunas medidas para evitar que sean acumulados demasiados datos, pero éstas pueden ser obviadas por el huésped: Se presenta un tiempo de espera en el que el lado del cliente de una interfaz puede dejar de consumir nuevos paquetes antes de que sea asumido que ha sido estancado, pero este tiempo de espera es bastante largo (60 segundos por defecto). Usando una conexión UDP en una interfaz rápida pueden acumularse fácilmente gigabytes de datos en ese tiempo. (CVE-2021-28715) El tiempo de espera podría incluso no dispararse nunca si el huésped consigue tener sólo una ranura libre en su página de anillo de cola RX y el siguiente paquete requeriría más de una ranura libre, lo que puede ser el caso cuando se usa OSG, XDP o hashing de software. (CVE-2021-28714)"
}
],
"lastModified": "2026-06-17T03:46:51.567",
"configurations": [
{
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