CVE-2025-40046

io_uring/zcrx: fix overshooting recv limit

HIGH
8.6
CVSS Score
Published: October 28, 2025 at 11:48 AM UTC
Updated: October 19, 2026 at 09:10 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH8.6
Exploit prediction
EPSS 0.3%

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/zcrx: fix overshooting recv limit It's reported that sometimes a zcrx request can receive more than was requested. It's caused by io_zcrx_recv_skb() adjusting desc->count for all received buffers including frag lists, but then doing recursive calls to process frag list skbs, which leads to desc->count double accounting and underflow.

Affected

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

6.156699ec9a23f85f1764183430209c741847c45f12
Vendor states this is fixed in 09cfd3c52ea76f43b3cb15e570aeddf633d65e80 (fixed)
Vendor states this is fixed in 8bcc9eaf1b19f1a7029cba19f6bd4122b40f6c4f (fixed)
Vendor states this is fixed in 6.15 (unaffected)
Vendor states this is fixed in 6.17.3 (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.

CVSS

8.6HIGHLinux
Vector?

Quick Info

StatusDEFERRED

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