What is CVE-2026-72493?

CVE-2026-72493 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.9 out of 10, affecting Linux kernel versions from 3.2.71 onward and patched in 7.1.5 and 7.2. CVE-2026-72493 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-72493?

CVE-2026-72493 has a CVSS score of 9.9 out of 10, rated Critical severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.

Is there a patch available for CVE-2026-72493?

Yes, CVE-2026-72493 has been patched. Fixed versions include 7.1.5 and 7.2. If you are running Linux kernel 3.2.71 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-72493 actively exploited?

CVE-2026-72493 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-72493

Critical

In the Linux kernel, the following vulnerability has been resolved: net: serialize netif_running() check in enqueue_to_backlog() Syzbot reported a KASAN slab-use-after-free in fib_rules_lookup(). The root cause is a race condition where packets can escape the backlog flushing during device unregistration (e.g., during netns exit). Commit e9e4dd3267d0 ("net: do not process device backlog during unregistration") introduced a lockless netif_running() check in enqueue_to_backlog() to prevent queuing packets to an unregistering device. However, this creates a TOCTOU race window. A lockless transmitter (like veth_xmit) can pass the check before dev_close() clears IFF_UP. If the transmitter is then delayed, flush_all_backlogs() can run and finish before the transmitter grabs the backlog lock and queues the packet. The packet then escapes the flush and triggers UAF later when processed. Fix this by moving the netif_running() check inside the backlog lock. This serializes the check with the flush work (which also grabs the lock). We then either queue the packet before the flush runs (so it gets flushed), or check netif_running() after the flush/close completes (so it gets dropped).

Package Linux Kernel

Published 2026-08-15

Last modified 2026-08-17

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

9.9

out of 10

Critical

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Vector string

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

Affected versions

Linux kernel versions 3.2.71, 3.4.111, 3.12.48, 3.14.54, 3.18.22, 4.1.9, 4.2 and later are affected. Fixed in 7.1.5, 7.2 and their respective stable series.

Affected from

≥ 3.2.71 ≥ 3.4.111 ≥ 3.12.48 ≥ 3.14.54 ≥ 3.18.22 ≥ 4.1.9 ≥ 4.2

Fixed in

✓ 7.1.5 7.1.x ✓ 7.2

References

2 total

Details

CVE ID CVE-2026-72493

Severity Critical

CVSS score 9.9 / 10

CVSS version 3.1

Published 2026-08-15

Modified 2026-08-17

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-72493?

CVE-2026-72493 is a Critical severity Linux kernel vulnerability with a CVSS score of 9.9 out of 10 . It affects Linux kernel versions from 3.2.71 onward and has been patched in 7.1.5 and 7.2. CVE-2026-72493 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-72493?

CVE-2026-72493 has a CVSS score of 9.9 out of 10, rated Critical severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
Is there a patch available for CVE-2026-72493?

Yes. CVE-2026-72493 has been patched. Fixed versions include 7.1.5 and 7.2. If you are running Linux kernel 3.2.71 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-72493 actively exploited?

No. CVE-2026-72493 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.