Linux Kernel GRO Zero-Copy Skb Merge Causing UAF
CVE-2026-46323 Published on June 9, 2026
net: gro: don't merge zcopy skbs
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.
Vulnerability Analysis
CVE-2026-46323 can be exploited with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
Write-what-where Condition
Any condition where the attacker has the ability to write an arbitrary value to an arbitrary location, often as the result of a buffer overflow.
Products Associated with CVE-2026-46323
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Affected Versions
Linux:- Version 753f1ca4e1e50248a1b760c9774d6d6b354562cc and below 3c6cc9f2ca65b6dd61b1af75452dc0e1cd0aad8d is affected.
- Version 753f1ca4e1e50248a1b760c9774d6d6b354562cc and below 1f9c828556416fbe3f49386708ce999fc4d4da06 is affected.
- Version 753f1ca4e1e50248a1b760c9774d6d6b354562cc and below 479084ae0e1d9cb7929cb4298d35623de189f80a is affected.
- Version 753f1ca4e1e50248a1b760c9774d6d6b354562cc and below e334cbf3388fd9334503a778a82d9e9f14dd2f71 is affected.
- Version 753f1ca4e1e50248a1b760c9774d6d6b354562cc and below 44bea2032af0425e4ce6d26a8af0ede79db49ec1 is affected.
- Version 753f1ca4e1e50248a1b760c9774d6d6b354562cc and below 4db79a322db8c97f7b73b8a347395ef4d685eb40 is affected.
- Version 6.0 is affected.
- Before 6.0 is unaffected.
- Version 6.1.176, <= 6.1.* is unaffected.
- Version 6.6.142, <= 6.6.* is unaffected.
- Version 6.12.92, <= 6.12.* is unaffected.
- Version 6.18.34, <= 6.18.* is unaffected.
- Version 7.0.11, <= 7.0.* is unaffected.
- Version 7.1, <= * is unaffected.
- Version 0:6.12.0-55.82.1.el10_0 and below * is unaffected.
- Version 0:5.14.0-687.22.1.el9_8 and below * is unaffected.
- Version 0:5.14.0-427.132.1.el9_4 and below * is unaffected.
- Version 0:5.14.0-570.123.1.el9_6 and below * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.