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Vulnerabilities

Vulnerability · CVE-2026-72323

ipv4: igmp: Fix potential UAF in igmp_gq_start_timer()

Published Aug 15, 2026 · catalog updated Oct 16, 2026 · ipv4: igmp: Fix potential

Check if you run it

No confirmed exploitation is on record for CVE-2026-72323. EPSS is 0.72%. Act only if a listed version of ipv4: igmp: Fix potential is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (ipv4: igmp: Fix potential).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.72%
Remediation
Not established
Affected products
Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: ipv4: igmp: Fix potential UAF in igmp_gq_start_timer() A race condition exists between device teardown (inetdev_destroy) and incoming IGMP query processing (igmp_rcv), leading to a Use-After-Free in the IGMP timer callback. During device destruction, inetdev_destroy() drops the primary reference to in_device, which can drop its refcount to 0. The actual freeing of in_device memory is deferred via RCU (using call_rcu()). Concurrently, igmp_rcv() runs under RCU read lock and obtains the in_device pointer. Because the memory is RCU-protected, CPU-0 can safely dereference in_device even if its refcount has hit 0. However, if CPU-0 calls igmp_gq_start_timer() and re-arms the timer, it attempts to acquire a reference using in_dev_hold(). This increments the refcount from 0 to 1, triggering a "refcount_t: addition on 0" warning. Since the in_device memory is still scheduled to be freed after the RCU grace period (as the free callback does not check the refcount again), the device is freed while the timer is still armed. When the timer expires, it accesses the freed memory, causing a kernel panic. Fix this by using refcount_inc_not_zero() (via a new helper in_dev_hold_safe()) to prevent acquiring a reference if the device is already being destroyed. If the refcount is 0, we do not arm the timer. A similar issue in IPv6 MLD is fixed in a subsequent patch.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Linux Kernel2.6.12 → 5.10.269

How to fix CVE-2026-72323

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-72323. EPSS is 0.72%. Act only if a listed version of ipv4: igmp: Fix potential is installed.

Which versions are affected?

Compare what you have installed with Kernel 2.6.12 → 5.10.269. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.72%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 15, 2026 · OpenSSF OSV / OSV Scanner

    Detected

    In the Linux kernel, the following vulnerability has been resolved: ipv4: igmp: Fix potential UAF in igmp_gq_start_timer() A race condition exists between device teardown (inetdev_destroy) and incoming IGMP query processing (igmp_rcv), leading to a Use-After-Free in the IGMP timer callback. During device destruction, inetdev_destroy() drops the primary reference to in_device, which can drop its re

  2. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 5.10.269

  3. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 5.10.269

  4. Oct 16, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    In the Linux kernel, the following vulnerability has been resolved: ipv4: igmp: Fix potential UAF in igmp_gq_start_timer() A race condition exists between device teardown (inetdev_destroy) and incoming IGMP query processing (igmp_rcv), leading to a Use-After-Free in the IGMP timer callback. During device destruction, inetdev_destroy() drops the primary reference to in_device, which can drop its re

Sources

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.