CVE-2026-23254

MEDIUM EPSS 1.7%
Published Mar 18, 20263mo ago · Modified Jun 17, 20261w ago
5.5 CVSS 3.1
Medium
Find Similar
Published Mar 18, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

Description

In the Linux kernel, the following vulnerability has been resolved: net: gro: fix outer network offset The udp GRO complete stage assumes that all the packets inserted the RX have the `encapsulation` flag zeroed. Such assumption is not true, as a few H/W NICs can set such flag when H/W offloading the checksum for an UDP encapsulated traffic, the tun driver can inject GSO packets with UDP encapsulation and the problematic layout can also be created via a veth based setup. Due to the above, in the problematic scenarios, udp4_gro_complete() uses the wrong network offset (inner instead of outer) to compute the outer UDP header pseudo checksum, leading to csum validation errors later on in packet processing. Address the issue always clearing the encapsulation flag at GRO completion time. Such flag will be set again as needed for encapsulated packets by udp_gro_complete().

CVSS Details

Base Score
5.5
Exploitability
1.8
Impact
3.6
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
1.7% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Affected Products 14

VendorProductVersionRange
linuxlinux_kernel*≥6.6.31  –  <6.6.124
linuxlinux_kernel*≥6.8.10  –  <6.9
linuxlinux_kernel*≥6.9.1  –  <6.12.70
linuxlinux_kernel*≥6.13  –  <6.18.10
linuxlinux_kernel6.9any
linuxlinux_kernel6.9any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any
linuxlinux_kernel6.19any

References 4

  • git.kernel.org https://git.kernel.org/stable/c/2e5edb69e5d0e23ef248c56fc977039268c77a7b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5c2c3c38be396257a6a2e55bd601a12bb9781507
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/9d40a85138568696387ef04cd004c64612a70874
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b83557bc6f560433fe5d727e241069f8db5ba709
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/2e5edb69e5d0e23ef248c56fc977039268c77a7b
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/5c2c3c38be396257a6a2e55bd601a12bb9781507
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/9d40a85138568696387ef04cd004c64612a70874
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/b83557bc6f560433fe5d727e241069f8db5ba709
    Patch