CVE-2026-25267

Executive Summary

CVE-2026-25267 is a high-severity memory corruption vulnerability (CVSS 7.8) in Qualcomm's QCA6698Au firmware that manifests when a non-secure loader rewrites page tables prior to secure memory initialization. The flaw is categorized as CWE-862 (Missing Authorization) and enables an attacker with local access and low privileges to achieve full compromise of confidentiality, integrity, and availability on affected devices. With no public PoC, no patch, and no known exploitation in the wild, organizations running Qualcomm-based hardware with QCA6698Au firmware — particularly Wi-Fi 6E/7 routers, access points, and embedded networking devices — face a latent but critical risk pending vendor remediation.

Technical Analysis

The vulnerability resides in the trust boundary between a non-secure firmware loader and the secure initialization path in Qualcomm's QCA6698Au chipset firmware. According to the NVD description, the specific failure mode is memory corruption that occurs when a non-secure loader rewrites page tables before secure memory initialization completes. This constitutes a temporal authorization failure: memory-management metadata (page tables) is being modified by a component operating outside the secure world prior to the establishment of the security boundary that should govern that memory region.

CWE-862 (Missing Authorization) is the assigned weakness class. In the context of firmware, this means the secure initialization routine fails to enforce an authorization check on who may modify critical memory structures. Because page tables are core memory-management primitives, their corruption can yield arbitrary read/write primitives, privilege escalation from non-secure to secure world, or complete denial of service (firmware hang/crash).

The CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) confirms:

• Attack Vector: Local — the attacker requires local execution context within the affected device (e.g., a co-located process, a privileged-but-non-secure application, or physical/adjacent access to a debug interface).
• Privileges Required: Low — the attacker does not need root/secure-world privileges to trigger the flaw.
• User Interaction: None — no victim action required.
• Scope: Unchanged — impact remains within the same security authority.

No further technical specifics (function names, register names, memory addresses, file paths) are available in the NVD description or CNA title. The QCA6698Au is a connectivity/SoC component typically found in high-end wireless infrastructure; the secure memory subsystem in question is the hardware-isolated trust zone used for secure boot, key storage, and cryptographic operations.

Exploitation Scenarios

No public PoC is available for CVE-2026-25267; the attack chain below is inferred from the vulnerability class (memory corruption via missing authorization during secure memory initialization) and the CVSS vector.

1. Reconnaissance / Target Identification. An attacker identifies a device running firmware for the Qualcomm QCA6698Au chipset — commonly Wi-Fi 6E/7 access points, mesh routers, or embedded CPE. Identification can be performed via Shodan dorks (product:"Qualcomm QCA6698", http.html:"qca6698", http.title:"Qualcomm") or via device discovery on the local network segment. Physical access or local code execution is required per the AV:L vector.

2. Privilege Positioning. The attacker obtains low-privileged local execution context on the device — for example, by compromising a non-secure application, abusing an exposed debug/console interface, or leveraging a separate lower-severity vulnerability to run code in the non-secure world.

3. Trigger Configuration. The attacker triggers conditions such that the non-secure loader is executed and rewrites page tables prior to the firmware's secure memory initialization sequence. Because the missing authorization check (CWE-862) allows modification of page-table entries from the non-secure domain, the attacker can cause the memory-management structures to point at attacker-controlled or maliciously modified physical memory.

4. Payload Execution / Impact. Once page tables are corrupted, consequences can include: (a) arbitrary read/write within the affected address space, (b) execution of attacker-controlled code with elevated (secure-world) privilege, (c) bypass of secure boot or key-derivation protections, and (d) persistent firmware-level compromise. The CVSS high subscores for Confidentiality, Integrity, and Availability (C:H/I:H/A:H) indicate that full loss of each is achievable.

5. Post-Exploitation. Given the chipset's role in secure boot and cryptographic key handling, an attacker who achieves secure-world code execution may extract device-unique secrets, install persistent implants, or pivot to the broader network via the compromised AP/router.

Impact Assessment

The blast radius is every device shipping QCA6698Au firmware that has not been updated with a vendor fix. Because this is a firmware-level memory corruption affecting secure memory initialization, impact extends to:

• Confidentiality (High): Compromise of cryptographic keys, secure-boot secrets, and trusted memory regions.
• Integrity (High): Modification of firmware behavior, persistence across reboots, and tampering with secure-world code.
• Availability (High): Corrupted page tables can crash or hang the device, causing complete loss of the affected network node.

Business impact depends on deployment role. In an enterprise wireless edge, a compromised access point or CPE can serve as a network foothold, enabling lateral movement into the corporate LAN. In critical infrastructure or OT environments, a persistent firmware implant on a connectivity device can be used for long-term surveillance or sabotage. As this is a local-attack vector, mass remote exploitation is unlikely, but targeted attacks — including supply-chain or insider scenarios — remain viable. EPSS is 0.00098 (0.7th percentile), meaning current observed exploitation likelihood is very low, and CISA KEV does not list it. This does not negate the severity for high-value targets relying on the chipset.

Detection Guidance

Sigma Rule

title: Potential QCA6698Au Page Table Corruption Attempt
id: 8c4b1f2a-7d3e-4a91-b2c5-9f0e6d3a1b77
status: experimental
description: Detects anomalous writes to page-table memory regions by non-secure loaders prior to secure memory initialization, indicative of CVE-2026-25267 exploitation.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-25267
author: Threat Intelligence
date: 2026/02/17
logsource:
  product: linux
  service: kernel
detection:
  selection:
    EventType: 'memory_write'
    MemoryRegion|contains: 'page_table'
    ProcessInitiator|contains: 'non_secure'
    InitPhase|contains: 'pre_secure_init'
  condition: selection
falsepositives:
  - Legitimate firmware update flows during controlled maintenance windows
level: high
tags:
  - attack.privilege_escalation
  - attack.t1068
  - cve.2026.25267

YARA Rule

rule CVE_2026_25267_QCA6698_PageTable_Corruption
{
    meta:
        description = "Detects firmware images or memory dumps exhibiting non-secure loader page-table rewrite patterns associated with CVE-2026-25267"
        author = "Threat Intelligence"
        date = "2026-02-17"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-25267"
        cve = "CVE-2026-25267"
        severity = "high"

    strings:
        $qca = "QCA6698" ascii wide nocase
        $ldr = "non-secure loader" ascii wide nocase
        $pt  = "page table" ascii wide nocase
        $sec = "secure memory init" ascii wide nocase

    condition:
        $qca and 2 of ($ldr, $pt, $sec)
}

Suricata IDS Rule

alert tcp $HOME_NET any -> $HOME_NET any (msg:"CVE-2026-25267 Qualcomm QCA6698Au Potential Firmware Page Table Manipulation"; flow:to_server,established; content:"QCA6698"; nocase; content:"page_table"; nocase; content:"secure_init"; nocase; classtype:attempted-admin; sid:2026252670; rev:1; reference:cve,2026-25267; metadata:created_at 2026_02_17, updated_at 2026_02_17;)

Elastic Detection

sequence by host.id with maxspan=5m
  [ process where process.name != null and process.args : "*loader*" and process.args : "*non-secure*" ]
  [ memory where memory.region : "page_table" and memory.protection_changed == true ]
  [ process where process.name : ("init", "secure_init", "tz_init") ]

Splunk SPL Query

index=firmware_logs (sourcetype=qualcomm:qca6698 OR sourcetype=embedded:boot)
| search ("non-secure loader" OR "non_secure_loader") AND ("page table" OR "page_table")
| stats count, values(caller_process) as callers, values(device_id) as devices by host
| where count > 0
| sort - count

Wazuh OSSEC Rule

<group name="qualcomm,cve-2026-25267,">
  <rule id="100767" level="12">
    <decoded_as>json</decoded_as>
    <field name="event_type">firmware_memory_write</field>
    <field name="component">non-secure-loader</field>
    <field name="target_region">page_table</field>
    <description>CVE-2026-25267: Possible non-secure loader rewrite of page tables prior to secure memory initialization on QCA6698Au firmware.</description>
    <mitre>
      <id>T1068</id>
    </mitre>
    <group>firmware_integrity,critical,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source).

1. Immediate Mitigations

• Restrict local access to affected devices: disable unused debug interfaces, UART/JTAG where feasible, and harden any local console or recovery mode.
• Enforce network segmentation so that non-secure user-space components cannot be compromised and used as a launch point.
• Monitor firmware integrity via secure-boot attestation where supported; alert on unexpected page-table region writes as per the detection rules above.
• Vendor contact: engage Qualcomm and the OEM to request emergency firmware remediation and an advisory tracking CVE-2026-25267.

2. Patch / Upgrade Steps

• No vendor patch is available as of this writing (no vendored fix, no OSV package, no CVE-referenced advisory). Continue tracking NVD and Qualcomm security bulletins.
• When firmware is released, update via verified signed firmware images only, and validate post-upgrade secure-boot state.

3. Long-Term Hardening

• Demand hardware-backed isolation between loader and secure memory init in future procurement.
• Require secure-boot and rollback-protection capabilities as procurement criteria for connectivity SoCs.
• Integrate firmware integrity monitoring into SOC workflows to detect page-table anomalies at the earliest boot stage.

References

• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25267
• Qualcomm Product Security: https://www.qualcomm.com/company/product-security/bulletins
• CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog (not listed as of this writing)
• MITRE ATT&CK T1068: https://attack.mitre.org/techniques/T1068/
• CWE-862 Missing Authorization: https://cwe.mitre.org/data/definitions/862.html

No exploit-in-the-wild evidence, no public PoC, and no threat-actor campaign known to be using CVE-2026-25267 at the time of writing.