Description

A vulnerability exists in an undisclosed BIG-IP Configuration utility page that may allow an attacker to spoof error messages  Impact: An attacker may trick authenticated BIG-IP users into accessing malicious links and reflect a spoofed error message in the victim's BIG-IP Configuration utility web browser session. This is a control plane issue; there is no data plane exposure. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "3.1",
  "pubDate": "2026-09-02T16:17:18.400Z",
  "pubdate": "2026-09-02T16:17:18.400Z",
  "executiveSummary": "A vulnerability exists within the BIG-IP Configuration utility that permits the spoofing of error messages within a user's browser session. This vulnerability is classified as a Reflected Cross-Site Scripting (XSS) or content injection flaw targeting the utility's web interface. The impact is limited to the control plane, meaning that while the integrity of the user's interface can be compromised, there is no direct exposure of the data plane or underlying traffic processed by the BIG-IP system.\nThe attack requires the victim to be an authenticated user of the BIG-IP Configuration utility. By convincing an authenticated user to interact with a malicious link, an attacker can reflect custom, misleading error messages directly into the victim’s session. This manipulation can be leveraged for social engineering, such as prompting the user to perform actions they otherwise would not, or to deceive the administrator regarding the state of the system. The risk resides in the potential for unauthorized interface manipulation and user deception within the administrative environment, although it does not grant the attacker direct system access or the ability to intercept traffic passing through the BIG-IP device.",
  "technicalDetails": "The vulnerability manifests as an improper validation or sanitization issue within an undisclosed page of the BIG-IP Configuration utility. This flaw enables an attacker to inject arbitrary content—specifically reflected error messages—into the web response provided to the authenticated user. Because the BIG-IP Configuration utility session context is maintained via the user's browser, the application fails to adequately encode or neutralize user-supplied input before rendering it back to the UI.\nThe attack flow begins when an attacker crafts a malicious URL containing a payload designed to trigger the error message generation mechanism in the target BIG-IP Configuration utility. The attacker then lures an authenticated administrator or user of the utility to click this link. Upon navigation, the BIG-IP utility processes the malicious input and reflects the spoofed error message within the legitimate web session context of the user. Because the message appears to originate from the trusted, local BIG-IP interface, the user is likely to perceive the spoofed error as a genuine system notification or application alert.\nThis is strictly a control plane vulnerability. The mechanism of exploitation relies on the reflection of parameters or input data back into the DOM (Document Object Model) of the configuration utility. This allows for the manipulation of the UI to display misleading information. The vulnerability does not provide a mechanism for remote code execution (RCE), privilege escalation, or unauthorized access to the underlying OS or the data plane. The primary impact is the loss of interface integrity, which can be weaponized for sophisticated social engineering campaigns against system administrators.\nThe requirement for victim authentication is a critical constraint, as the attacker must ensure that the target has an active, valid session with the BIG-IP Configuration utility at the time the malicious link is accessed. Successful exploitation does not require advanced network positioning, as the attacker only needs the ability to deliver the link to the user. Post-exploitation, the malicious link may persist in the victim's history or continue to be visible as long as the spoofed message remains displayed in the current browser session, facilitating further deception or redirecting the user to attacker-controlled external resources."
}