UNKNOWN CVSS N/A
Published: 2026-11-03

CVE-2026-99254

Software Component Security Advisory (CVE-2026-99254)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2026-99254 impacting Software Component. Evaluated with CVSS Base Score of N/A (UNKNOWN).

Original NVD Description

Source: NIST NVD
In the Linux kernel, the following vulnerability has been resolved: io_uring: don't flood a cancelling task with task_work io_ring_exit_work() asks each task which has used the ring to remove its tctx node, by task_work, and repeats that until the list is empty. io_tctx_exit_cb() doesn't touch the node while the task is in io_uring_cancel_generic(), which removes all the nodes at its end. So the work item queues the callback again as soon as it has completed, for nothing. That is more than a waste of time. task_work_run() only returns when it finds the list empty. If the rings are released from inside the cancellation, because requests of other rings held the last references to their files, up to 64 work items keep sending callbacks to the one task which is running them. It never finds the list empty, never gets back to the cancellation, the nodes stay, and so it goes on: a task with 60 pairs of rings which poll each other ran 280000 callbacks in 5 seconds, 20 seconds after exit_group(). It ends when all the senders happen to be late at the same time. Until then the task keeps a CPU and the work items busy. An exiting task can't be killed meanwhile. execve() cancels the requests in the same way, so a live task can get stuck there as well, for minutes. If it takes more than five, the work items run into the WARN_ON_ONCE(time_after(jiffies, timeout)) of io_ring_exit_work(). No privilege is needed for any of this. If the callback has met a task in cancellation, wait a little before it is sent again. Nobody has to wake the work item up for that: either the node is gone by then, or it is the turn of the next round.

📊 CVSS v3.1 Metric Breakdown

🎯 Affected Versions Matrix

Affected Product Generic/Unknown / Software Component
Affected Versions Unspecified
Weakness Enumeration CWE-Not-Specified

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-2026-99254 impacting Software Component.

⚡ Nuclei Detection Template (YAML) cve-2026-99254.yaml
id: cve-2026-99254

info:
  name: Software Component - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: unknown
  description: |
    Automated signature & scanner for CVE-2026-99254 affecting Software Component.
    Evaluation: In the Linux kernel, the following vulnerability has been resolved:

io_uring: don't flood a cancelling task with task_work

io_ring_exit_work() ...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2026-99254
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: N/A
    cve-id: CVE-2026-99254
    cwe-id: CWE-Not-Specified
  tags: cve,cve-2026-99254,generic,software,unknown

http:
  - method: GET
    path:
      - "{BaseURL}/"
      - "{BaseURL}/api/"
    matchers-condition: and
    matchers:
      - type: status
        status:
          - 200
      - type: word
        words:
          - "Server"
        part: body
🐍 PoC Exploit & Verification Probe (Python 3) poc_cve-2026-99254.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2026-99254
# Target: Software Component | CVSS: N/A (UNKNOWN)
# Educational & Security Audit Purpose Only

import requests
import sys

def verify_vulnerability(target_url):
    print(f"[*] Auditing {target_url} for CVE-2026-99254 (Software Component)...")
    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 Software Component scope (Unspecified).")
        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-2026-99254.sh
# Recommended Remediation & Patching Commands for CVE-2026-99254
# 1. Update package via distribution package manager:
sudo apt-get update && sudo apt-get --only-upgrade install software 2>/dev/null || \
sudo dnf upgrade software 2>/dev/null || \
sudo yum update software

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

# 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

Authorities
  • No records filed in this category.
Distributions
  • No records filed in this category.
Technical Analysis
  • No records filed in this category.

❓ Frequently Asked Questions (FAQ) & Remediation Guide

How do I fix CVE-2026-99254 in Software Component?

Review vendor-specific security notices and update Software Component 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-2026-99254?

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-2026-99254?

CVE-2026-99254 is classified with a CVSS 3.1 Base Score of N/A (UNKNOWN). Check the metric breakdown above for attack vector requirements.

Risk Snapshot
N/A
UNKNOWN SEVERITY
CVE ID CVE-2026-99254
Weakness CWE-Not-Specified
Vendor Generic/Unknown
Product Software Component
Published 2026-11-03
Vector N/A