MEDIUM CVSS 5.5
Published: 2026-01-13

CVE-2025-71087

linux linux_kernel Security Advisory (CVE-2025-71087)
↗ Official NIST NVD Record
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CyberVault Technical Summary

Analyst Synthesis

Technical analysis, exploit verification, and patch instructions for CVE-2025-71087 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: iavf: fix off-by-one issues in iavf_config_rss_reg() There are off-by-one bugs when configuring RSS hash key and lookup table, causing out-of-bounds reads to memory [1] and out-of-bounds writes to device registers. Before commit 43a3d9ba34c9 ("i40evf: Allow PF driver to configure RSS"), the loop upper bounds were: i <= I40E_VFQF_{HKEY,HLUT}_MAX_INDEX which is safe since the value is the last valid index. That commit changed the bounds to: i <= adapter->rss_{key,lut}_size / 4 where `rss_{key,lut}_size / 4` is the number of dwords, so the last valid index is `(rss_{key,lut}_size / 4) - 1`. Therefore, using `<=` accesses one element past the end. Fix the issues by using `<` instead of `<=`, ensuring we do not exceed the bounds. [1] KASAN splat about rss_key_size off-by-one BUG: KASAN: slab-out-of-bounds in iavf_config_rss+0x619/0x800 Read of size 4 at addr ffff888102c50134 by task kworker/u8:6/63 CPU: 0 UID: 0 PID: 63 Comm: kworker/u8:6 Not tainted 6.18.0-rc2-enjuk-tnguy-00378-g3005f5b77652-dirty #156 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: iavf iavf_watchdog_task Call Trace: <TASK> dump_stack_lvl+0x6f/0xb0 print_report+0x170/0x4f3 kasan_report+0xe1/0x1a0 iavf_config_rss+0x619/0x800 iavf_watchdog_task+0x2be7/0x3230 process_one_work+0x7fd/0x1420 worker_thread+0x4d1/0xd40 kthread+0x344/0x660 ret_from_fork+0x249/0x320 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 63: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x7f/0x90 __kmalloc_noprof+0x246/0x6f0 iavf_watchdog_task+0x28fc/0x3230 process_one_work+0x7fd/0x1420 worker_thread+0x4d1/0xd40 kthread+0x344/0x660 ret_from_fork+0x249/0x320 ret_from_fork_asm+0x1a/0x30 The buggy address belongs to the object at ffff888102c50100 which belongs to the cache kmalloc-64 of size 64 The buggy address is located 0 bytes to the right of allocated 52-byte region [ffff888102c50100, ffff888102c50134) The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x102c50 flags: 0x200000000000000(node=0|zone=2) page_type: f5(slab) raw: 0200000000000000 ffff8881000418c0 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080200020 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888102c50000: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc ffff888102c50080: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc >ffff888102c50100: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc ^ ffff888102c50180: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc ffff888102c50200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

📊 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-193

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-2025-71087 impacting linux linux_kernel.

⚡ Nuclei Detection Template (YAML) cve-2025-71087.yaml
id: cve-2025-71087

info:
  name: linux linux_kernel - Security Advisory & Vulnerability Scan
  author: cybervault-security-intel
  severity: medium
  description: |
    Automated signature & scanner for CVE-2025-71087 affecting linux linux_kernel.
    Evaluation: In the Linux kernel, the following vulnerability has been resolved:

iavf: fix off-by-one issues in iavf_config_rss_reg()

There are off-by-one bugs w...
  reference:
    - https://cybervault-cve.pages.dev/cve/CVE-2025-71087
  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-2025-71087
    cwe-id: CWE-193
  tags: cve,cve-2025-71087,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-2025-71087.py
# Proof-of-Concept Exploit & Verification Probe for CVE-2025-71087
# 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-2025-71087 (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-2025-71087.sh
# Recommended Remediation & Patching Commands for CVE-2025-71087
# 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-2025-71087 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-2025-71087?

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-2025-71087?

CVE-2025-71087 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-2025-71087
Weakness CWE-193
Vendor linux
Product linux_kernel
Published 2026-01-13
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H