In the Linux kernel, the following vulnerability has been resolved:
Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"
I've found that pynfs COMP6 now leaves the connection or lease in a
strange state, which causes CLOSE9 to hang indefinitely. I've dug
into it a little, but I haven't been able to root-cause it yet.
However, I bisected to commit 48aab1606fa8 ("NFSD: Remove the cap on
number of operations per NFSv4 COMPOUND").
Tianshuo Han also reports a potential vulnerability when decoding
an NFSv4 COMPOUND. An attacker can place an arbitrarily large op
count in the COMPOUND header, which results in:
[ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total
pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO),
nodemask=(null),cpuset=/,mems_allowed=0
when NFSD attempts to allocate the COMPOUND op array.
Let's restore the operation-per-COMPOUND limit, but increased to 200
for now.
Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"
I've found that pynfs COMP6 now leaves the connection or lease in a
strange state, which causes CLOSE9 to hang indefinitely. I've dug
into it a little, but I haven't been able to root-cause it yet.
However, I bisected to commit 48aab1606fa8 ("NFSD: Remove the cap on
number of operations per NFSv4 COMPOUND").
Tianshuo Han also reports a potential vulnerability when decoding
an NFSv4 COMPOUND. An attacker can place an arbitrarily large op
count in the COMPOUND header, which results in:
[ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total
pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO),
nodemask=(null),cpuset=/,mems_allowed=0
when NFSD attempts to allocate the COMPOUND op array.
Let's restore the operation-per-COMPOUND limit, but increased to 200
for now.
Metrics
Affected Vendors & Products
| Vendors | Products |
|---|---|
| Linux |
|
No data.
No data.
No data.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 21 Nov 2025 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND" I've found that pynfs COMP6 now leaves the connection or lease in a strange state, which causes CLOSE9 to hang indefinitely. I've dug into it a little, but I haven't been able to root-cause it yet. However, I bisected to commit 48aab1606fa8 ("NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"). Tianshuo Han also reports a potential vulnerability when decoding an NFSv4 COMPOUND. An attacker can place an arbitrarily large op count in the COMPOUND header, which results in: [ 51.410584] nfsd: vmalloc error: size 1209533382144, exceeds total pages, mode:0xdc0(GFP_KERNEL|__GFP_ZERO), nodemask=(null),cpuset=/,mems_allowed=0 when NFSD attempts to allocate the COMPOUND op array. Let's restore the operation-per-COMPOUND limit, but increased to 200 for now. | |
| Title | Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND" | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-11-21T10:21:35.540Z
Reserved: 2025-04-16T07:20:57.179Z
Link: CVE-2025-40210
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2025-11-21T11:15:49.110
Modified: 2025-11-21T15:13:13.800
Link: CVE-2025-40210
Redhat
No data.
OpenCVE Enrichment
No data.