Описание
In the Linux kernel, the following vulnerability has been resolved:
NFSD: Limit the number of concurrent async COPY operations
Nothing appears to limit the number of concurrent async COPY
operations that clients can start. In addition, AFAICT each async
COPY can copy an unlimited number of 4MB chunks, so can run for a
long time. Thus IMO async COPY can become a DoS vector.
Add a restriction mechanism that bounds the number of concurrent
background COPY operations. Start simple and try to be fair -- this
patch implements a per-namespace limit.
An async COPY request that occurs while this limit is exceeded gets
NFS4ERR_DELAY. The requesting client can choose to send the request
again after a delay or fall back to a traditional read/write style
copy.
If there is need to make the mechanism more sophisticated, we can
visit that in future patches.
A flaw was found in the Linux kernel's Network File System Daemon (NFSD). An attacker can exploit this by initiating an unlimited number of concurrent asynchronous copy operations. This can lead to resource exhaustion and a Denial of Service (DoS) condition, making the system unresponsive to legitimate requests.
Меры по смягчению последствий
To mitigate this issue, restrict access to the NFS service to trusted clients and networks using firewall rules. If the NFS service is not required, disable it to prevent exploitation.
To disable the NFS server:
sudo systemctl stop nfs-server
sudo systemctl disable nfs-server
Note that disabling the NFS server will prevent all NFS shares from being accessible.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel | Will not fix | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Will not fix | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Will not fix | ||
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2025:6966 | 13.05.2025 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2025:6966 | 13.05.2025 |
Показывать по
Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: NFSD: Limit the number of concurrent async COPY operations Nothing appears to limit the number of concurrent async COPY operations that clients can start. In addition, AFAICT each async COPY can copy an unlimited number of 4MB chunks, so can run for a long time. Thus IMO async COPY can become a DoS vector. Add a restriction mechanism that bounds the number of concurrent background COPY operations. Start simple and try to be fair -- this patch implements a per-namespace limit. An async COPY request that occurs while this limit is exceeded gets NFS4ERR_DELAY. The requesting client can choose to send the request again after a delay or fall back to a traditional read/write style copy. If there is need to make the mechanism more sophisticated, we can visit that in future patches.
In the Linux kernel, the following vulnerability has been resolved: NFSD: Limit the number of concurrent async COPY operations Nothing appears to limit the number of concurrent async COPY operations that clients can start. In addition, AFAICT each async COPY can copy an unlimited number of 4MB chunks, so can run for a long time. Thus IMO async COPY can become a DoS vector. Add a restriction mechanism that bounds the number of concurrent background COPY operations. Start simple and try to be fair -- this patch implements a per-namespace limit. An async COPY request that occurs while this limit is exceeded gets NFS4ERR_DELAY. The requesting client can choose to send the request again after a delay or fall back to a traditional read/write style copy. If there is need to make the mechanism more sophisticated, we can visit that in future patches.
NFSD: Limit the number of concurrent async COPY operations
In the Linux kernel, the following vulnerability has been resolved: N ...
In the Linux kernel, the following vulnerability has been resolved: NFSD: Limit the number of concurrent async COPY operations Nothing appears to limit the number of concurrent async COPY operations that clients can start. In addition, AFAICT each async COPY can copy an unlimited number of 4MB chunks, so can run for a long time. Thus IMO async COPY can become a DoS vector. Add a restriction mechanism that bounds the number of concurrent background COPY operations. Start simple and try to be fair -- this patch implements a per-namespace limit. An async COPY request that occurs while this limit is exceeded gets NFS4ERR_DELAY. The requesting client can choose to send the request again after a delay or fall back to a traditional read/write style copy. If there is need to make the mechanism more sophisticated, we can visit that in future patches.
EPSS
5.5 Medium
CVSS3