UBUNTU-CVE-2026-99055: Medium severity ubuntu/linux-hwe-edge vulnerability

Published Oct 23, 2026
·
Updated

In the Linux kernel, the following vulnerability has been resolved: tcp: reject netiov in zerocopy receive mapping hints After copying a readable prefix, receivefallbacktocopy() asks tcpzerocopysethintforskb() where page mapping can resume. If the next skb is unreadable, findnextmappablefrag() passes its netiov fragment to canmapfrag(). skbfragpage() returns NULL for a netiov, but canmapfrag() dereferences it in PageCompound(). A v7.2 KASAN run on a connected TCP socket with 64 readable bytes followed by a 4096-byte NETIOVDMABUF fragment reported: BUG: KASAN: null-ptr-deref in canmapfrag tcpzerocopyreceive -> canmapfrag Kernel panic - not syncing: KASAN: paniconwarn set The diagnostic inserted the netiov directly because the test host has no devmem-capable NIC. Hardware end-to-end reachability remains untested and requires CONFIGNETDEVMEM plus a supported DMA-buf-bound RX queue. Reject all netiov fragments before skbfragpage(). This covers both DMABUF and IOURING netiov types while leaving page-backed checks unchanged. With the guard, the same queue copied the readable prefix, returned a 4096-byte skip hint, and completed without a fault.

Affected Software

138 affected componentsFixes available
ubuntu/linux-hwe-edge*
ubuntu/linux-aws-5.0*
ubuntu/linux-aws-5.3*
ubuntu/linux-azure*
ubuntu/linux-azure-5.3*
ubuntu/linux-azure-edge*
ubuntu/linux-gcp*
ubuntu/linux-gcp-5.3*
ubuntu/linux-gke-4.15*
ubuntu/linux-gke-5.4*
ubuntu/linux-gkeop-5.4*
ubuntu/linux-hwe*
ubuntu/linux-hwe-edge*
ubuntu/linux-oem*
ubuntu/linux-oracle-5.0*
ubuntu/linux-oracle-5.3*
ubuntu/linux-aws-5.11*
ubuntu/linux-aws-5.13*
ubuntu/linux-aws-5.8*
ubuntu/linux-azure-5.11*
ubuntu/linux-azure-5.13*
ubuntu/linux-azure-5.8*
ubuntu/linux-azure-fde*
ubuntu/linux-gcp-5.11*
ubuntu/linux-gcp-5.13*
ubuntu/linux-gcp-5.8*
ubuntu/linux-gke*
ubuntu/linux-gke-5.15*
ubuntu/linux-gkeop*
ubuntu/linux-gkeop-5.15*
ubuntu/linux-hwe-5.11*
ubuntu/linux-hwe-5.13*
ubuntu/linux-hwe-5.8*
ubuntu/linux-intel-5.13*
ubuntu/linux-oem-5.10*
ubuntu/linux-oem-5.13*
ubuntu/linux-oem-5.6*
ubuntu/linux-oracle-5.11*
ubuntu/linux-oracle-5.13*
ubuntu/linux-oracle-5.8*
ubuntu/linux-raspi2*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.11*
ubuntu/linux-riscv-5.8*
ubuntu/linux-allwinner-5.19*
ubuntu/linux-aws-5.19*
ubuntu/linux-aws-6.2*
ubuntu/linux-aws-6.5*
ubuntu/linux-azure-5.19*
ubuntu/linux-azure-6.2*
ubuntu/linux-azure-6.5*
ubuntu/linux-azure-fde-5.19*
ubuntu/linux-azure-fde-6.2*
ubuntu/linux-gcp-5.19*
ubuntu/linux-gcp-6.2*
ubuntu/linux-gcp-6.5*
ubuntu/linux-hwe-5.19*
ubuntu/linux-hwe-6.2*
ubuntu/linux-hwe-6.5*
ubuntu/linux-intel-iot-realtime*
ubuntu/linux-lowlatency-hwe-5.19*
ubuntu/linux-lowlatency-hwe-6.2*
ubuntu/linux-lowlatency-hwe-6.5*
ubuntu/linux-nvidia-6.2*
ubuntu/linux-nvidia-6.5*
ubuntu/linux-oem-5.17*
ubuntu/linux-oem-6.0*
ubuntu/linux-oem-6.1*
ubuntu/linux-oem-6.5*
ubuntu/linux-oracle-6.5*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-5.19*
ubuntu/linux-riscv-6.5*
ubuntu/linux-starfive-5.19*
ubuntu/linux-starfive-6.2*
ubuntu/linux-starfive-6.5*
ubuntu/linux-aws-6.14*
ubuntu/linux-aws-6.17*
ubuntu/linux-aws-7.0<7.0.0-1017.18~24.04.1
7.0.0-1017.18~24.04.1
ubuntu/linux-azure-6.11*
ubuntu/linux-azure-6.14*
ubuntu/linux-azure-6.17*
ubuntu/linux-azure-7.0*
ubuntu/linux-azure-fde-6.14*
ubuntu/linux-azure-fde-6.17*
ubuntu/linux-azure-fde-7.0<7.0.0-1019.19~24.04.1
7.0.0-1019.19~24.04.1
ubuntu/linux-azure-nvidia-6.14*
ubuntu/linux-gcp-6.11*
ubuntu/linux-gcp-6.14*
ubuntu/linux-gcp-7.0<7.0.0-1017.19~24.04.1
7.0.0-1017.19~24.04.1
ubuntu/linux-hwe-6.11*
ubuntu/linux-hwe-6.14*
ubuntu/linux-hwe-6.17*
ubuntu/linux-hwe-7.0*
ubuntu/linux-lowlatency-hwe-6.11*
ubuntu/linux-nvidia-6.11*
ubuntu/linux-nvidia-6.17*
ubuntu/linux-nvidia-7.0*
ubuntu/linux-oem-6.11*
ubuntu/linux-oem-6.14*
ubuntu/linux-oem-6.17*
ubuntu/linux-oem-6.8*
ubuntu/linux-oracle-6.14*
ubuntu/linux-oracle-6.17*
ubuntu/linux-oracle-7.0<7.0.0-1016.18~24.04.1
7.0.0-1016.18~24.04.1
ubuntu/linux-raspi-realtime*
ubuntu/linux-realtime*
ubuntu/linux-riscv*
ubuntu/linux-riscv-6.14*
ubuntu/linux-riscv-6.17*
ubuntu/linux-riscv-7.0<7.0.0-43.43.1~24.04.2
7.0.0-43.43.1~24.04.2
ubuntu/linux-realtime-6.14*
ubuntu/linux-realtime-6.17*
ubuntu/linux<7.3.0-10.10
7.3.0-10.10
ubuntu/linux-aws<7.3.0-1004.4
7.3.0-1004.4
ubuntu/linux-azure<7.3.0-1004.4
7.3.0-1004.4
ubuntu/linux-azure-fde<7.3.0-1004.5
7.3.0-1004.5
ubuntu/linux-gcp<7.3.0-1004.4
7.3.0-1004.4
ubuntu/linux-oracle<7.3.0-1004.4
7.3.0-1004.4
ubuntu/linux-raspi<7.3.0-1004.4
7.3.0-1004.4
ubuntu/linux-realtime<7.3.0-10.10.1
7.3.0-10.10.1
ubuntu/linux-riscv<7.3.0-10.10.1
7.3.0-10.10.1
ubuntu/linux<7.0.0-43.43
7.0.0-43.43
ubuntu/linux-aws<7.0.0-1017.18
7.0.0-1017.18
ubuntu/linux-azure<7.0.0-1020.21
7.0.0-1020.21
ubuntu/linux-azure-fde<7.0.0-1019.19
7.0.0-1019.19
ubuntu/linux-gcp<7.0.0-1017.19
7.0.0-1017.19
ubuntu/linux-gke<7.0.0-1010.11
7.0.0-1010.11
ubuntu/linux-ibm<7.0.0-1018.18
7.0.0-1018.18
ubuntu/linux-nvidia*
ubuntu/linux-nvidia-bos*
ubuntu/linux-oem-7.0<7.0.0-1018.18
7.0.0-1018.18
ubuntu/linux-oracle<7.0.0-1016.18
7.0.0-1016.18
ubuntu/linux-raspi*
ubuntu/linux-realtime<7.0.0-43.43.1
7.0.0-43.43.1
ubuntu/linux-riscv*
ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade ubuntu/linux-aws-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1017.18~24.04.1
  2. Upgrade

    Upgrade ubuntu/linux-azure-fde-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1019.19~24.04.1
  3. Upgrade

    Upgrade ubuntu/linux-gcp-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1017.19~24.04.1
  4. Upgrade

    Upgrade ubuntu/linux-oracle-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1016.18~24.04.1
  5. Upgrade

    Upgrade ubuntu/linux-riscv-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-43.43.1~24.04.2
  6. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 7.3.0-10.10
  7. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 7.3.0-1004.4
  8. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 7.3.0-1004.4
  9. Upgrade

    Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.

    Fixed in 7.3.0-1004.5
  10. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 7.3.0-1004.4
  11. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 7.3.0-1004.4
  12. Upgrade

    Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.

    Fixed in 7.3.0-1004.4
  13. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 7.3.0-10.10.1
  14. Upgrade

    Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.

    Fixed in 7.3.0-10.10.1
  15. Upgrade

    Upgrade ubuntu/linux to a version that resolves this vulnerability.

    Fixed in 7.0.0-43.43
  16. Upgrade

    Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.

    Fixed in 7.0.0-1017.18
  17. Upgrade

    Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.

    Fixed in 7.0.0-1020.21
  18. Upgrade

    Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.

    Fixed in 7.0.0-1019.19
  19. Upgrade

    Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.

    Fixed in 7.0.0-1017.19
  20. Upgrade

    Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.

    Fixed in 7.0.0-1010.11
  21. Upgrade

    Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.

    Fixed in 7.0.0-1018.18
  22. Upgrade

    Upgrade ubuntu/linux-oem-7.0 to a version that resolves this vulnerability.

    Fixed in 7.0.0-1018.18
  23. Upgrade

    Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.

    Fixed in 7.0.0-1016.18
  24. Upgrade

    Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.

    Fixed in 7.0.0-43.43.1

Event History

Oct 23, 2026
CVE Published
via OSV·01:17 PM
Data Sourced
via OSV·01:17 PM
DescriptionSeverityAffected Software

Frequently Asked Questions

1

What conditions are needed to trigger the fault?

The issue occurs during TCP zerocopy receive handling when a readable prefix is followed by an unreadable net_iov fragment. The described reproduction used 64 readable bytes followed by a 4096-byte NET_IOV_DMABUF fragment on a connected TCP socket.

2

Which configurations are most likely to be exposed?

Hardware end-to-end reachability requires CONFIG_NET_DEVMEM and an RX queue that supports DMA-buf binding. The report notes that this hardware path was not tested because the test host did not have a devmem-capable NIC.

3

What is the likely impact if the vulnerable path is reached?

A net_iov fragment can cause a NULL pointer dereference in can_map_frag() when skb_frag_page() returns NULL. The supplied diagnostic shows a KASAN null-pointer-dereference report and a kernel panic when panic_on_warn is enabled.

4

How can affected behavior be identified?

Look for KASAN reports identifying a null-pointer dereference in can_map_frag() through tcp_zerocopy_receive. The reported call path includes tcp_zerocopy_receive followed by can_map_frag().

Company

Resources

Contact

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