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CVE-2026-31660

MEDIUMCVSS 5.5/10EPSS 0.11%

Last modified

CVE-2026-31660 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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. EPSS estimates a 0.11% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.11%

1.8th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 5.5.1, < 5.10.253—
LinuxLinux Kernel>= 5.11, < 5.15.203—
LinuxLinux Kernel>= 5.16, < 6.1.169—
LinuxLinux Kernel>= 6.2, < 6.6.135—
LinuxLinux Kernel>= 6.7, < 6.12.82—
LinuxLinux Kernel>= 6.13, < 6.18.23—
LinuxLinux Kernel>= 6.19, < 6.19.13—
LinuxLinux Kernel5.5—
LinuxLinux Kernel7.0Rc1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-31660?
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.
How severe is CVE-2026-31660?
CVE-2026-31660 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.11% probability of exploitation in the next 30 days.
How do I fix CVE-2026-31660?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-31660?

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Source: NVD / NIST