MEDIUM CVSS 5.5
Published: 2026-05-06

CVE-2026-43188

linux linux_kernel Security Advisory (CVE-2026-43188)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-43188 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: ceph: do not propagate page array emplacement errors as batch errors When fscrypt is enabled, move_dirty_folio_in_page_array() may fail because it needs to allocate bounce buffers to store the encrypted versions of each folio. Each folio beyond the first allocates its bounce buffer with GFP_NOWAIT. Failures are common (and expected) under this allocation mode; they should flush (not abort) the batch. However, ceph_process_folio_batch() uses the same `rc` variable for its own return code and for capturing the return codes of its routine calls; failing to reset `rc` back to 0 results in the error being propagated out to the main writeback loop, which cannot actually tolerate any errors here: once `ceph_wbc.pages` is allocated, it must be passed to ceph_submit_write() to be freed. If it survives until the next iteration (e.g. due to the goto being followed), ceph_allocate_page_array()'s BUG_ON() will oops the worker. Note that this failure mode is currently masked due to another bug (addressed next in this series) that prevents multiple encrypted folios from being selected for the same write. For now, just reset `rc` when redirtying the folio to prevent errors in move_dirty_folio_in_page_array() from propagating. Note that move_dirty_folio_in_page_array() is careful never to return errors on the first folio, so there is no need to check for that. After this change, ceph_process_folio_batch() no longer returns errors; its only remaining failure indicator is `locked_pages == 0`, which the caller already handles correctly.

📊 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 NVD-CWE-noinfo

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-2026-43188 impacting linux linux_kernel.

⚡ Nuclei Detection Template (YAML) cve-2026-43188.yaml
id: cve-2026-43188

info:
  name: linux linux_kernel - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2026-43188 affecting linux linux_kernel.
    Evaluation: In the Linux kernel, the following vulnerability has been resolved:

ceph: do not propagate page array emplacement errors as batch errors

When fscryp...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-43188
  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-2026-43188
    cwe-id: NVD-CWE-noinfo
  tags: cve,cve-2026-43188,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-2026-43188.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-43188
# 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-2026-43188 (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-2026-43188.sh
# Recommended Remediation & Patching Commands for CVE-2026-43188
# 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.

🔗 Verified Technical References

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-43188 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-2026-43188?

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-2026-43188?

CVE-2026-43188 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-2026-43188
Weakness NVD-CWE-noinfo
Vendor linux
Product linux_kernel
Published 2026-05-06
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H