Disclosed vulnerability
Brave: indirect prompt injection in Perplexity Comet via hidden Reddit comment steals Gmail OTP
AIR-2025-0108 AIR record · 2025-08-perplexity-comet-brave-injection
From the supporting source
Traditional protections such as same-origin policy (SOP) or cross-origin resource sharing (CORS) are all effectively uselessbrave.com
The record
Disclosed
2025-08-20
Occurred
2025-07-25
Vendor
Perplexity
Product
Perplexity Comet
Risk domain
Privacy › Data exfiltration channels
Also touches
Credential theft, Privilege escalation, Confused deputy
System type
Generative model
Who acted
Agent acted — Comet navigated to Gmail and exfiltrated the OTP
Attack surface
Browser agent
Autonomy level
Semi-autonomous
Initial vector
Indirect prompt injection web page
Impact type
Data exfiltration, Credential theft, Account takeover
Confidence
High
Submitted by
EAI Internal
Crosswalk
- OWASP Agentic Top 10 (2026)
- ASI02 – Tool Misuse and Exploitation
- MITRE ATLAS
- AML.T0024 – Exfiltration via AI Inference API
- NIST AI RMF
- MAP 4.2
- EU AI Act
- Article 10
- ISO/IEC
- TR 24028; 23894
- AIUC-1
- A. Data & Privacy
- Scope
- tool misuse
- Mitigation
- Monitor network traffic for anomalous patterns; Restrict egress destinations.
- Taxonomy
- Enkrypt AI agent risk taxonomy · Black-Box Red Teaming of Agentic AI: A Taxonomy-Driven Framework for Automated Risk Discovery
Blast radius
all Comet users who summarize an attacker-controlled page
Capability abused
Defense & remediation
Recorded defense
none effective at disclosure time; user/page content not separated in the model context
Guardrail kinds
None
Guardrail outcome
Not applicable
Fix shipped
partial - Perplexity patched 2025-07-27 and again by 2025-08-13, but Brave's update states the attack class was still not fully mitigated
Taxonomy & references
Curator notes
First widely-cited agentic-browser injection disclosure. Payload hidden behind a Reddit spoiler tag; on 'Summarize this page' Comet navigated to the Perplexity account page to read the user's email, then to Gmail to read a one-time password, then posted both back as a Reddit reply. No known real-world victim. Brave timeline: reported 2025-07-25, disclosed 2025-08-20. | Merged from duplicate id `2025-08-perplexity-comet-reddit-injection`. Also reported as: 'Indirect prompt injection in Perplexity Comet: page content drives account takeover and OTP theft'.
Supporting sources
Cite as
Enkrypt AI. "Brave: indirect prompt injection in Perplexity Comet via hidden Reddit comment steals Gmail OTP". AIR, AIR-2025-0108. https://agentincident.vercel.app/i/AIR-2025-0108/ (accessed 2026-10-19).