Description

Mitigation bypass in the Add-ons Manager component. This vulnerability was fixed in Firefox 154 and Firefox ESR 153.1.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-08-18T13:17:36.683Z",
  "pubdate": "2026-08-18T13:17:36.683Z",
  "executiveSummary": "This security analysis addresses a mitigation bypass vulnerability residing within the Add-ons Manager component of the affected software. The vulnerability allows a malicious actor to circumvent existing security controls designed to restrict unauthorized extension manipulation or administrative state changes.\nThe flaw directly impacts Firefox versions prior to 154 and Firefox ESR versions prior to 153.1. Successful exploitation of this vulnerability undermines the integrity of the browser extension architecture, potentially allowing unauthorized modifications or operations that bypass intended security boundaries.\nThe risk implications include the potential degradation of browser security guarantees enforced by the Add-ons Manager. While specific attacker capabilities and interaction requirements depend on the execution context, mitigation bypass vulnerabilities generally require the target to interact with malicious content or leverage secondary execution vectors to achieve the desired state deviation.\nRemediation requires updating the affected software to the specified patched versions where the underlying logic flaw within the Add-ons Manager component has been formally resolved.",
  "technicalDetails": "The vulnerability is classified as a mitigation bypass affecting the Add-ons Manager component responsible for governing the lifecycle, installation, and permission states of browser extensions and plugins within Firefox.\nThe root cause stems from a logic flaw or insufficient validation within the security checks enforced during add-on processing or state transitions. When security mitigations are implemented to restrict specific privileged operations within the Add-ons Manager, flaws in the boundary enforcement logic can permit an unauthorized workflow to be executed.\nThe affected versions are strictly identified as Firefox prior to version 154 and Firefox ESR prior to version 153.1. The vulnerability exists within the codebase handling internal component communications, policy evaluations, or API calls exposed by the Add-ons Manager subsystem.\nThe attack flow typically proceeds through a sequence where an adversary constructs an exploitation vector designed to trigger the vulnerable execution path within the Add-ons Manager. Because the component handles sensitive administrative logic, failing to properly validate preconditions or state boundaries allows the bypass of intended defensive mechanisms.\nDuring exploitation, the malicious payload or interaction leverages the flawed logic to bypass restrictions that would normally block unauthorized modifications or anomalous operations within the extension environment. This may involve manipulating internal component APIs, injecting specific parameters, or abusing exposed interfaces to force the Add-ons Manager into accepting an invalid state.\nAuthentication and privilege requirements for exploitation are mediated by the context in which the Add-ons Manager operates, though typical attack scenarios involve untrusted web content or compromised extensions attempting to escalate capabilities or bypass security controls. Network exposure is local to the browser instance, requiring the execution context to interact with the vulnerable component.\nThe post-exploitation impact includes the successful circumvention of security boundaries enforced by the Add-ons Manager, which can compromise the integrity of the browser's extension security model and pave the way for further unauthorized actions within the application environment."
}