CVE-2026-48125 faisalman CVE debrief

Who should care

Developers and administrators using UAParser.js in their applications should be aware of this vulnerability and take necessary actions to mitigate it. They should verify their systems for potential exposure and apply compensating controls if necessary. Additionally, they should monitor for suspicious activity related to the Client Hints API. It is essential for them to understand the potential impact of this vulnerability on their systems and take proactive measures to prevent exploitation. This includes reviewing the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance, and planning vendor-supported updates or mitigations through normal change control where exposure is confirmed. Compensating controls for exposed systems should be reviewed while remediation is scheduled and verified. Relevant monitoring, detection, and logs for exposed assets that need extra review should be checked. Exceptions, retest remediated assets, and close the item only after evidence is documented. Asset inventory and security team should be aware of this vulnerability and its potential impact on their systems and applications. Vulnerability management and security teams should prioritize this vulnerability and ensure that necessary actions are taken to mitigate it. This may involve coordinating with developers and administrators to ensure that patches are applied and compensating controls are in place. By taking proactive measures, organizations can reduce the risk of exploitation and minimize the potential impact of this vulnerability on their systems and applications. The security team should also review and update their incident response plan to include procedures for responding to potential exploitation of this vulnerability. This includes identifying and isolating affected systems, containing the damage, and restoring systems to a known good state. By being proactive and taking necessary actions, organizations can minimize the risk of exploitation and protect their systems and applications from potential attacks. Security teams should also consider implementing additional security controls, such as web application firewalls and intru.

Technical summary

The UAParser.js library had a regular expression denial-of-service vulnerability from version 2.0.1 until 2.0.10 when using the Client Hints API. An attacker could cause excessive CPU time by sending a crafted Sec-CH-UA-Model header to an application that calls UAParser(headers).withClientHints(). The vulnerability is due to catastrophic backtracking in the device regex because Client Hints values are copied without the UA_MAX_LENGTH limit used for User-Agent values. This issue can be mitigated by updating UAParser.js to version 2.0.10 or later.

Defensive priority

Medium-priority defensive actions are recommended due to the potential for denial-of-service attacks.

Recommended defensive actions

• Apply the patch by updating UAParser.js to version 2.0.10 or later.
• Verify systems for potential exposure and apply compensating controls if necessary.
• Monitor for suspicious activity related to the Client Hints API.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record and NVD detail provide information about the vulnerability in UAParser.js. The issue was fixed in version 2.0.10. Users should verify their systems and apply patches accordingly. It is essential to note that the vulnerability exists when using the Client Hints API, and an attacker could cause excessive CPU time by sending a crafted Sec-CH-UA-Model header to an application that calls UAParser(headers).withClientHints(). The problem is due to catastrophic backtracking in the device regex because Client Hints values are copied without the UA_MAX_LENGTH limit used for User-Agent values. To mitigate this vulnerability, developers and administrators should be aware of the issue and take necessary actions.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.