CVE-2026-53175

Aliases:UBUNTU-CVE-2026-53175DEBIAN-CVE-2026-53175CGA-3p8h-8cfc-v2q6CGA-5q66-8xq3-hggvCGA-839m-x4xw-cg4hCGA-9c84-44j8-fpppCGA-cpp7-876v-97qhCGA-hxwg-phrx-2jx5CGA-m4rh-m69f-rwr4CGA-pm77-xj2v-7vhr
Advisory lineage Upstream: 0 Downstream: 24
Modified
Published: 25 Jun 2026, 08:38
Last modified:01 Sept 2026, 12:04

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.8 CRITICAL
v3.1 (cve.org)
EPSS Score
0.31% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

25 Jun 2026, 08:38
Published
Vulnerability first disclosed
01 Sept 2026, 12:04
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: inet: frags: fix use-after-free caused by the fqdir_pre_exit() flush On netns teardown, fqdir_pre_exit() walks the fqdir rhashtable and flushes every fragment queue that is not yet complete using inet_frag_queue_flush(). That helper frees all the skbs queued on the fragment queue but does not set INET_FRAG_COMPLETE, and leaves q->fragments_tail and q->last_run_head pointing at the freed skbs. The queue itself stays in the rhashtable. fqdir_pre_exit() first lowers high_thresh to 0 to stop new queue lookups, but it cannot stop a fragment that already obtained the queue through inet_frag_find() earlier and stalled just before taking the queue lock. Once that fragment resumes after the flush and takes the queue lock, it passes the INET_FRAG_COMPLETE check and then dereferences the freed fragments_tail. inet_frag_queue_insert() reads FRAG_CB() and ->len of that pointer and, on the append path, writes ->next_frag, causing a slab use-after-free. IPv6, nf_conntrack_reasm6 and 6lowpan reassembly share the same flush path and are affected as well. Reset rb_fragments, fragments_tail and last_run_head in inet_frag_queue_flush() so a flushed queue no longer points at the freed skbs. A fragment that resumes after the flush and takes the queue lock then finds an empty queue and starts a new run instead of dereferencing the freed fragments_tail. ip_frag_reinit() already performed this reset after its own flush, so drop the now duplicate code there.

CVSS Metrics

  • v4.0•HIGH•Score: 7.3CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
  • v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.31%• Percentile: 24%

Techniques & Countermeasures

  • CWE-416•Use After Free

    The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

  • CWE-825•Expired Pointer Dereference

    The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.

Affected Systems

  • chainguard•linux-aws-6.18

    < 6.18.38-r0

  • chainguard•linux-azure-6.18

    < 6.18.38-r0

  • chainguard•linux-gcp-6.18

    < 6.18.38-r0

  • chainguard•linux-gcp-6.18-bootc-boot-installed

    < 6.18.38-r0

  • chainguard•linux-qemu-6.18

    < 6.18.38-r0

  • chainguard•linux-qemu-6.18-bootc-boot-installed

    < 6.18.38-r0

  • chainguard•linux-qemu-melange

    < 6.18.38-r0

  • chainguard•linux-vmware-6.18

    < 6.18.38-r0

  • debian•linux

    < 7.0.13-1

  • ubuntu•linux

    all | < 7.0.0-29.29

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    all | < 7.0.0-1010.10

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.14

    all

  • ubuntu•linux-aws-6.17

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-7.0

    all | < 7.0.0-1010.10~24.04.1

  • ubuntu•linux-azure

    all | all | < 7.0.0-1011.11

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.11

    all

  • ubuntu•linux-azure-6.14

    all

  • ubuntu•linux-azure-6.17

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-7.0

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | all | < 7.0.0-1010.10

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.14

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-nvidia-6.14

    all

  • ubuntu•linux-bluefield

    all

  • ubuntu•linux-gcp

    all | all | all | < 7.0.0-1010.10

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.11

    all

  • ubuntu•linux-gcp-6.14

    all

Showing first 50 affected entries in server-rendered view.

References (24)