MEDIUM CVSS 5.5
Published: 2026-07-13

CVE-2026-53365

linux linux_kernel Security Advisory (CVE-2026-53365)
↗ Official NIST NVD Record
Seeking technical exploit breakdowns or verified PoC code for CVE-2026-53365?
🔬 Search Writeups & Exploit Archive →

CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-53365 impacting linux linux_kernel. Evaluated with CVSS Base Score of 5.5 (MEDIUM).

Original NVD Description

Source: NIST NVD
In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: fix zerocopy completion for multi-skb sends When a large message is fragmented into multiple skbs, the zerocopy uarg is only allocated and attached to the last skb in the loop. Non-final skbs carry pinned user pages with no completion tracking, so the kernel has no way to notify userspace when those pages are safe to reuse. If the loop breaks early the uarg is never allocated at all, leaking pinned pages with no completion notification. Fix this by following the approach used by TCP: allocate the zerocopy uarg (if not provided by the caller) before the send loop and attach it to every skb via skb_zcopy_set(), which takes a reference per skb. Each skb's completion properly decrements the refcount, and the notification only fires after the last skb is freed. On failure, if no data was sent, the uarg is cleanly aborted via net_zcopy_put_abort(). This issue was initially discovered by sashiko while reviewing commit 1cb36e252211 ("vsock/virtio: fix MSG_ZEROCOPY pinned-pages accounting") but was pre-existing.

📊 CVSS v3.1 Metric Breakdown

Attack Vector
Local (AV:L)
Requires local system execution permissions
Attack Complexity
Low (AC:L)
No specialized conditions required
Privileges Required
Low (PR:L)
Standard user access required
User Interaction
None (UI:N)
Zero human interaction required
Scope
Unchanged (S:U)
Confined to same security context
Confidentiality
None (C:N)
No data confidentiality impact
Integrity
None (I:N)
No system modification impact
Availability
High (A:H)
Total denial of service or shutdown

🎯 Affected Versions Matrix

Affected Product linux / linux_kernel
Affected Versions *
Weakness Enumeration CWE-401

Security Research Arsenal: Nuclei Detection Template & PoC Exploit Probe

High-Intent Research Tool

Ready-to-use security scanner signatures, active verification probe skeletons, and remediation playbooks for CVE-2026-53365 impacting linux linux_kernel.

⚡ Nuclei Detection Template (YAML) cve-2026-53365.yaml
id: cve-2026-53365

info:
  name: linux linux_kernel - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-53365 affecting linux linux_kernel.
    Evaluation: In the Linux kernel, the following vulnerability has been resolved:

vsock/virtio: fix zerocopy completion for multi-skb sends

When a large message i...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-53365
  classification:
    cvss-metrics: CVSS:3.1/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
    cvss-score: 5.5
    cve-id: CVE-2026-53365
    cwe-id: CWE-401
  tags: cve,cve-2026-53365,linux,linux_kernel,medium

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "linux_kernel"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-53365.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-53365
# Target: linux linux_kernel | CVSS: 5.5 (MEDIUM)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-53365 (linux linux_kernel)...")
    headers = {
        "User-Agent": "CyberVault-Audit-Scanner/2.0",
        "Accept": "*/*"
    }
    try:
        r = requests.get(f"{target_url.rstrip('/')}/", headers=headers, timeout=8, verify=False)
        print(f"[+] Server Response: HTTP {r.status_code} | Server Banner: {r.headers.get('Server', 'Unknown')}")
        if r.status_code < 500:
            print(f"[!] Target reachable. Verify version against linux linux_kernel scope (*).")
        return True
    except Exception as e:
        print(f"[-] Connection Error: {e}")
        return False

if __name__ == '__main__':
    url = sys.argv[1] if len(sys.argv) > 1 else "http://localhost:8080"
    verify_vulnerability(url)
🛡️ Quick Patch & Remediation Script (Bash) patch_cve-2026-53365.sh
# Recommended Remediation & Patching Commands for CVE-2026-53365
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install linux_kernel 2>/dev/null || \
sudo dnf upgrade linux_kernel 2>/dev/null || \
sudo yum update linux_kernel

# 2. Inspect installed package versions for vulnerable scope:
dpkg -l | grep -i linux_kernel 2>/dev/null || rpm -qa | grep -i linux_kernel

# 3. Docker container & image vulnerability scan:
docker scan $(docker ps -q) 2>/dev/null || echo "Verify upstream base images in Dockerfile."

🛡️ Remediation & Security Action

  • Authoritative Guidance: Follow distribution-specific vendor security notices. Advisory status and package patches vary by distribution release.
  • Verification: Inspect installed binary packages and package manager versions for affected component releases.
  • Upstream Status: Upgrade to verified non-backdoored upstream versions or roll back to known-clean stable releases.
⚠️ Disclaimer: Follow vendor-specific advisories for your operating system. CyberVault does not fabricate unsupported remediation scripts.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-53365 in linux linux_kernel?

Review vendor-specific security notices and update linux linux_kernel packages to the latest patched release immediately. If immediate upgrading is restricted by change windows, isolate affected network ports and enforce least-privilege access boundaries.

Is there an active exploit or public PoC for CVE-2026-53365?

No weaponized public exploit has been confirmed in public threat streams yet. Continuous surveillance is active across GitHub and security feeds.

What is the CVSS 3.1 severity rating and impact for CVE-2026-53365?

CVE-2026-53365 is classified with a CVSS 3.1 Base Score of 5.5 (MEDIUM). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
5.5
MEDIUM SEVERITY
CVE ID CVE-2026-53365
Weakness CWE-401
Vendor linux
Product linux_kernel
Published 2026-07-13
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H