CVE-2026-99284
Received
Received - Intake
Linux Kernel SKB Shared Fragment Propagation Flaw
Vulnerability report for CVE-2026-99284, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-07
Last updated on: 2026-11-07
Assigner: kernel.org
Description
Description
In the Linux kernel, the following vulnerability has been resolved:
net: skbuff: propagate shared-frag marker in skb_zerocopy()
skb_zerocopy() moves frag descriptors from @from into @to and takes a
reference on each frag, but it does not copy skb_shinfo(from)->flags into
skb_shinfo(to)->flags. A destination skb holding the same page-cache
backed frags as the source therefore reports skb_has_shared_frag() as
false.
That breaks the invariant relied on by later in-place writers. ESP input
checks skb_has_shared_frag() before deciding whether an uncloned
nonlinear skb can skip skb_cow_data(); with the marker lost, an skb that
skb_zerocopy() built for nfnetlink_queue or for an openvswitch upcall is
decrypted in place, letting an unprivileged user write into the page
cache of a root-owned read-only file.
Propagate SKBFL_SHARED_FRAG when frag descriptors are copied, as done for
the other frag-transfer helpers.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
