Vulnary
← back to the feed
Critical· 9.1official fix available

CVE-2026-23455

A flaw in the Linux kernel’s netfilter H.323 connection tracking can let an attacker read memory outside the intended bounds, potentially exposing sensitive data or crashing the system. The bug is triggered by malformed packets and requires no special privileges or user interaction. The issue has been fixed in recent kernel releases.

publishedApr 3, 2026
last modifiedJul 24, 2026
sourcesNVD
severity · cvss
9.1
critical · how bad it is
exploitation · epss
1%
68th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 25, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

All Linux kernel users running versions before the patch, especially those using netfilter’s H.323 connection tracking. Typical users include system administrators and operators of Linux servers and network devices.

02

Real-world impact

An attacker could send crafted network packets to a vulnerable Linux system, causing the kernel to read memory it shouldn’t. This could leak confidential information or cause a denial‑of‑service by crashing the kernel.

03

Why this severity

The CVSS score of 9.1 reflects that the vulnerability is exploitable over the network, requires no privileges, and can compromise confidentiality and availability. The lack of a required user interaction and the high impact on the system make it critical.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade the Linux kernel to a version that includes the patch for nf_conntrack_h323.
  2. 02Restart the system to load the updated kernel.

NVD-referenced vendor advisory

05

Timeline

  1. Apr 3, 2026 · Apr 3, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 24, 2026 · 11d ago
    Advisory updated
    The NVD record was last revised.
  3. Jul 26, 2026 · 10d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactNone
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →