CVE-2026-46323
Received Received - Intake
Linux Kernel GRO Zerocopy Use-After-Free

Publication date: 2026-06-09

Last updated on: 2026-06-09

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: net: gro: don't merge zcopy skbs skb_gro_receive() can currently copy frags between the source and GRO skb, without checking the zerocopy status, and in particular the SKBFL_MANAGED_FRAG_REFS flag. When SKBFL_MANAGED_FRAG_REFS is set, the skb doesn't hold a reference on the pages in shinfo->frags. Appending those frags to another skb's frags without fixing up the page refcount can lead to UAF. When either the last skb in the GRO chain (the one we would append frags to) or the source skb is zerocopy, don't merge the skbs.
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Meta Information
Published
2026-06-09
Last Modified
2026-06-09
Generated
2026-06-09
AI Q&A
2026-06-09
EPSS Evaluated
N/A
NVD
CVE-2026-46323
EUVD
EUVD-2026-35413
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *
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Exploitability
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's network code, specifically in the Generic Receive Offload (GRO) functionality. The function skb_gro_receive() can copy fragments (frags) between source and GRO socket buffers (skbs) without properly checking the zerocopy status or the SKBFL_MANAGED_FRAG_REFS flag. When this flag is set, the skb does not hold a reference on the pages in the fragments, so appending these fragments to another skb without adjusting the page reference count can lead to a use-after-free (UAF) condition.

The fix prevents merging skbs when either the last skb in the GRO chain or the source skb is zerocopy, thereby avoiding the unsafe reference handling.

Impact Analysis

This vulnerability can lead to a use-after-free (UAF) condition in the Linux kernel's network stack. UAF vulnerabilities can cause system instability, crashes, or potentially allow attackers to execute arbitrary code or escalate privileges by exploiting the freed memory.

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