Bug 2461486 (CVE-2026-31660)

Summary: CVE-2026-31660 kernel: nfc: pn533: allocate rx skb before consuming bytes
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Near Field Communication (NFC) pn533 driver. This vulnerability arises from an issue in how the driver manages receive buffers. When processing incoming data, the driver may attempt to write to a non-existent buffer if a new one fails to allocate. This can lead to a system crash, resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-04-24 15:04:20 UTC 
In the Linux kernel, the following vulnerability has been resolved:

nfc: pn533: allocate rx skb before consuming bytes

pn532_receive_buf() reports the number of accepted bytes to the serdev
core. The current code consumes bytes into recv_skb and may already hand
a complete frame to pn533_recv_frame() before allocating a fresh receive
buffer.

If that alloc_skb() fails, the callback returns 0 even though it has
already consumed bytes, and it leaves recv_skb as NULL for the next
receive callback. That breaks the receive_buf() accounting contract and
can also lead to a NULL dereference on the next skb_put_u8().

Allocate the receive skb lazily before consuming the next byte instead.
If allocation fails, return the number of bytes already accepted.
Comment 1 Keith Grant 2026-04-24 22:16:35 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042403-CVE-2026-31660-9293@gregkh/T