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Advisories › ACVE-2026-0438

ACVE-2026-0438

Exposed files, browsing data or browser actions on instructions from a malicious extension: the built-in agents in Chrome, Edge, Opera Neon, Perplexity Comet and Claude in Chrome, in normal browsing.

Exposure

Harness
Chrome Gemini, Edge Copilot, Opera Neon, Perplexity Comet or Claude in Chrome with the built-in agent enabled — confirmed, forever.security
Model
any — unconfirmed
Goal
Any ordinary browsing task handled by the built-in browser agent (goal not stated by the source) — unconfirmed
Tools and settings
Browser extensions and the built-in browser-agent capabilities — confirmed, www.bleepingcomputer.com
Approval
The demonstrated agents used their existing browser privileges to read data or take actions — detected, forever.security
Input controlled by
tool-provider
What the agent does
The browser agent reads local or browser data, takes screenshots or acts on websites under extension-controlled instructions.
Harm
data-exfiltration
Reach
Browser data, local files and websites available to the browser — confirmed, www.bleepingcomputer.com (project files, a browser session, the network)

Reproducibility: partial (vulnerable components are not confirmed obtainable; trigger not published)

Severity
HIGH
Status
Unverified
Kind
Code
Modified
2026-09-25
Aliases
CVE-2026-0628, CVE-2026-55945
Affected
  • AgentHarness: chrome-gemini — all versions
  • AgentHarness: edge-copilot — all versions
  • AgentHarness: opera-neon — all versions
  • AgentHarness: perplexity-comet — all versions
  • AgentHarness: claude-in-chrome — all versions
Harness/product
chrome-gemini + edge-copilot + opera-neon + perplexity-comet + claude-in-chrome
Classes
tool-poisoning; data-exfiltration; over-privileged-combination; CWE-693
Taxonomy
ASI: ASI01; ASI: ASI04; ASI: ASI02; ATLAS: AML.T0051.001; ATLAS: AML.T0112.000
First reported
2026-09-16 — Forever Security
Licence
CC-BY-4.0 advisories; MIT code

Claims

Confirmed means the statement matches the cited primary source. Nothing on this page has been reproduced.

ClaimStatusSourceChecked
Identifier CVE-2026-0628Confirmedcveawg.mitre.org2026-09-24
Identifier CVE-2026-55945Confirmedcveawg.mitre.org2026-09-24
Severity HIGH; matches ADP/NVDConfirmedcveawg.mitre.org2026-09-24

In the wild

demonstrated

Description

What

Forever Security and BleepingComputer reported five browser-agent demonstrations under the BragJack name. A malicious extension could cause the built-in assistants to read local or browser data, take screenshots or act on websites; Chrome and Edge assigned CVE identifiers.

Detection

The researchers demonstrated the behavior across five browser agents.

Fix

Keep browsers and agent extensions updated, remove untrusted extensions and avoid granting broad extension permissions.

Fix

Update the affected browsers and remove untrusted extensions.

  • Reconfigure browser.extensions to remove untrusted extensions and restrict permissions. The reports identify malicious extensions as the common input to the browser agents. Owner: operator

References

ARTICLE

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