Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
Sources: National Vulnerability Database, CISA KEV, Exploit-DB
CVE-2026-19396 Overview
CVE-2026-19396 is a cryptographic weakness in the ASUS RT-BE57 router firmware. The IFTTT pairing token generator uses a predictable seed in its pseudo-random number generator (PRNG), classified as [CWE-337]. An unauthenticated attacker within adjacent network range can derive the pairing token by observing values from an administrator-initiated IFTTT pairing session. Successful token derivation allows the attacker to read and modify router settings, compromising confidentiality and integrity of the device configuration.
Critical Impact
An adjacent, unauthenticated attacker can recover the IFTTT pairing token and gain read/write access to router configuration during an active pairing session.
Affected Products
- ASUS RT-BE57 router firmware
- IFTTT pairing token generation subsystem
- Devices with IFTTT integration enabled by an administrator
Discovery Timeline
- 2026-10-07 - CVE CVE-2026-19396 published to NVD
- 2026-10-07 - Last updated in NVD database
Technical Details for CVE-2026-19396
Vulnerability Analysis
The vulnerability resides in how the ASUS RT-BE57 generates pairing tokens for IFTTT integration. The firmware seeds its PRNG with a predictable value, which collapses the entropy of the token space. An attacker who observes any public parameters exchanged during an administrator-initiated IFTTT pairing session can reconstruct the PRNG state. From that state, the attacker derives the pairing token used to authenticate IFTTT requests to the router. The adjacent-network requirement means the attacker must be on the same local segment or within wireless range of the device.
Root Cause
The root cause is the use of a non-cryptographic or deterministic seed for the PRNG that generates the IFTTT pairing token. [CWE-337] (Predictable Seed in Pseudo-Random Number Generator) applies directly. Secure token generation requires a cryptographically secure random source seeded with sufficient entropy from a hardware or kernel-provided entropy pool.
Attack Vector
Exploitation requires adjacent network access and the ability to observe the pairing exchange. The administrator must initiate IFTTT pairing for the attack window to open. Once the attacker captures the observable values, token derivation is performed offline. The attacker then submits authenticated IFTTT API requests to read or alter router configuration, including network settings, access controls, or forwarding rules.
No verified public exploit code is available. Refer to the ASUS Security Advisory for technical details.
Detection Methods for CVE-2026-19396
Indicators of Compromise
- Unexpected IFTTT API requests to the router outside of administrator-initiated pairing windows
- Router configuration changes without a corresponding admin login event in device logs
- Wireless clients associating during a pairing window that do not match known administrator devices
Detection Strategies
- Review router system logs for IFTTT pairing attempts and subsequent configuration-change events
- Correlate wireless association logs with pairing-session timestamps to identify unauthorized nearby clients
- Monitor outbound traffic from the router for IFTTT callbacks that were not provisioned by an administrator
Monitoring Recommendations
- Alert on any modification to firewall, DNS, or port-forwarding settings on the RT-BE57
- Capture and retain wireless probe and association logs during IFTTT pairing operations
- Enable syslog forwarding from the router to a central log store for correlation with network telemetry
How to Mitigate CVE-2026-19396
Immediate Actions Required
- Apply the firmware update referenced in the ASUS Security Advisory as soon as it is available for the RT-BE57
- Disable IFTTT integration on the router until the patched firmware is installed
- Perform IFTTT pairing only from a wired administrative host and in a controlled environment free of untrusted wireless clients
Patch Information
ASUS has published remediation guidance under the Security Update for ASUS Router Firmware section. Administrators should consult the ASUS Security Advisory for the specific firmware build that addresses CVE-2026-19396 on the RT-BE57 and apply it through the router's web UI or ASUS firmware update mechanism.
Workarounds
- Disable the IFTTT feature in the router's administration interface if it is not required
- Restrict wireless range during pairing by temporarily lowering radio transmit power or pairing over a wired connection
- Rotate administrator credentials and audit configured IFTTT applets after any suspected exposure
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
Sources: National Vulnerability Database, CISA KEV, Exploit-DB
