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CVE-2025-40210

Revert "NFSD: Remove the cap on number of operations per NFSv4 COMPOUND"

HIGH
7.5
CVSS Score
Published: November 21, 2025 at 10:21 AM UTC
Updated: October 19, 2026 at 07:10 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Linux Kernel· Linux
90%
48aab1606fa80027143a445224f552b4eeea845b6.17
Vendor states this is fixed in 3e7f011c255582d7c914133785bbba1990441713 (fixed)
Vendor states this is fixed in b3ee7ce432289deac87b9d14e01f2fe6958f7f0b (fixed)
Vendor states this is fixed in 6.17 (unaffected)
Vendor states this is fixed in 6.17.8 (unaffected)
Vendor states this is fixed in 6.18 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (2)

Source: cverecord
https://git.kernel.org/stable/c/b3ee7ce432289deac87b9d14e01f2fe6958f7f0b
Source: cverecord
https://git.kernel.org/stable/c/3e7f011c255582d7c914133785bbba1990441713

CVSS

7.5HIGHLinux
Vector?

Quick Info

StatusDEFERRED

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