Aiman Al-hadhrami LinkedIn vulnerability

Security Report: link Preview Update Failure on LinkedIn Enabling Attacker Deception and Phishing Attacks

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LinkedIn Link Preview Mismatch: A Gateway to Deception and Phishing Attacks

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Introduction

In today's digital landscape, social media platforms play a critical role in how information is shared and consumed. Link previews — the snippets showing images, titles, and descriptions when users paste URLs — have become a key feature to help users verify content before clicking. However, inconsistencies or flaws in how these previews are handled can expose users to deception, phishing, and other cyber threats.

The flaw exists in the LinkedIn mobile application, where the preview displayed for a link where the preview displayed for a link does not update correctly if a malicious URL is injected before publishing. This leads to a mismatch between the displayed preview and the actual link destination, posing significant risks of user deception and abuse.

This repot presents a security issue responsibly discovered and reported by independent cybersecurity researcher Aiman Al-Hadhrami.

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Summary of Security Issue: Native UI Deception via Link Previews

1. User Interaction Is Expected and Routine

The attack only requires a user to click a link in a LinkedIn post — a normal, platform-native action. This clearly qualifies as likely user interaction under LinkedIn’s vulnerability disclosure policy.

2. Native UI Deception, Not External Social Engineering

This vulnerability arises from a design flaw in LinkedIn’s link preview system. When a malicious link is posted, LinkedIn automatically generates a trusted visual preview that can misrepresent the actual destination.

• The deception is embedded within LinkedIn’s own UI.
• No attacker-driven manipulation or off-platform trickery is involved.
• Users are misled by what appears to be a legitimate, LinkedIn-generated preview.

3. Clearly Within In-Scope Policy Criteria

LinkedIn’s policy states:

> “Implementation and design issues that substantially impact LinkedIn members’ data or infrastructure are in scope.”

This vulnerability qualifies because it:

• Abuses LinkedIn’s branding and trust model.
• Enables phishing, credential theft, and potential malware delivery.
• Does so entirely using LinkedIn’s built-in functionality, without exploiting external services or bypassing traditional security controls.

4. Reproducible with a Clear Technical Root Cause

The issue is easily reproducible and is caused by a consistent, identifiable behavior in the link preview generation process.

5. Real-World Impact

This vulnerability has clear potential for large-scale abuse by malicious actors who can craft LinkedIn posts with legitimate-looking previews that direct users to harmful destinations — leveraging LinkedIn’s own trust signals to increase success rates.

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Comparison with Other Platforms

During testing, the same steps were reproduced across several popular messaging and social media platforms, including X (formerly Twitter), Threads, WhatsApp, Signal, and Telegram, I found that only LinkedIn — along with one other unspecified app — retains the initial link preview even after the user replaces the URL before publishing.

In contrast, all other tested platforms correctly update the preview to reflect the new destination URL, thereby preventing any mismatch between the preview and the actual link.

This behavior appears to be platform-specific to LinkedIn, and represents a deviation from the more secure and user-transparent design patterns followed by other major social platforms.

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Platform-Specific Behavior: App vs. Web

"Interestingly, this issue appears to be limited to the LinkedIn mobile application; when performing the same steps via the LinkedIn web interface in a browser, the preview either updates correctly or does not persist once the URL is injected."

This suggests that the flaw may be tied to how the mobile app handles UI state and link preview caching, further supporting its alignment with CWE-451 (UI Misrepresentation) and CWE-345 (Insufficient Verification of Data Authenticity).

Such discrepancies between app and web behavior could increase the risk of exploitation on mobile platforms, where users are less likely to inspect actual URLs before clicking.

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Phishing via Link Preview Mismatch – LinkedIn Job-Seeker Exploitation Scenario

Example:

An attacker creates a LinkedIn post that appears to promote job opportunities from a reputable company, such as:

https://careers.microsoft.com/openings

LinkedIn instantly generates a trusted preview using Microsoft’s branding, job title, and professional imagery — creating strong visual credibility and making the post appear completely legitimate.

Before publishing, the attacker injects a malicious phishing URL into the original link:

https://2u.pw/Semzr

However, LinkedIn does not invalidate or regenerate the preview after the URL injection. As a result, the post still displays a Microsoft-branded preview, but the visible link now leads to a fake login page designed to steal credentials.

Real-World Exploitation Scenario: Job-Seeker in Distress

Imagine a recent graduate or unemployed professional desperately looking for a job.

They come across this LinkedIn post showing an official Microsoft job offer, complete with branding and job descriptions — seemingly shared by a recruiter or hiring manager.

Out of urgency and hope, they:

• Click the link.
• Land on a perfectly cloned login page.
• Enter their LinkedIn credentials — or worse, corporate or email credentials used for job applications.

Result:

• Their account is compromised.
• Their data is harvested.
• They may be locked out of their LinkedIn profile during critical application periods.
• Or worse, the attacker uses the stolen account to spread more phishing through their network — amplifying the attack.

Security and Ethical Implications

This flaw allows attackers to:

• Exploit human trust in professional networks.
• Create targeted phishing attacks under the guise of opportunity.
• Attackers can use LinkedIn ads to target vulnerable job seekers, increasing the success of phishing attacks.
• Harvest credentials, personal information, or sensitive documents (CVs, passports, etc.).
• Cause psychological harm to people already in distress due to unemployment.

The emotional and professional impact can be devastating, especially for vulnerable users. This is not just a visual mismatch — it is a trust-based attack vector that hijacks the core purpose of LinkedIn: connecting people with real opportunities.

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Security Impact

• User Deception: Users may trust the content based on a legitimate-looking preview, unaware that the actual destination is malicious.
• Exploitation via Sponsored Ads: Attackers can use LinkedIn’s paid ads to increase the reach and credibility of malicious posts, targeting specific professional groups and making phishing attacks more effective.
• Legal issue: Using previews based on content from trusted institutions, companies, or organizations may be exploited for phishing or deception and could lead to legal issues.
• Phishing Facilitation: Attackers can present safe-looking previews while linking to phishing sites designed to steal login credentials, banking information, or personal data.
• Sensitive Data Theft: Exploiting this flaw can lead users to fake portals that harvest medical records, financial credentials, personal identification data, and even corporate login information.
• Malware & Spyware Installation: Victims may be redirected to malicious websites that automatically download spyware, keyloggers, ransomware, or other stealth malware.
• Surveillance and Espionage: Malicious actors may use this to target executives, journalists, or government employees, injecting spyware to monitor communications or extract sensitive intelligence.

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Technical Breakdown

• LinkedIn relies on Open Graph tags to fetch preview metadata.
• The preview is generated only when the first URL is pasted.
• When a malicious URL is injected before publishing, LinkedIn does not re-fetch or validate the new link’s metadata.
• This creates a visual mismatch between the displayed preview and the actual link.
• Clicking the visible link in the post, leads to a destination completely unrelated to the image, title, or description shown

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CWE and CAPEC Classifications

• CAPEC-98 – Phishing
• CAPEC-125 – URL Manipulation
• CWE-451 – User Interface Misrepresentation of Critical Information
• CWE-345 – Insufficient Verification of Data Authenticity

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Recommendations for LinkedIn

• Automatically invalidate and regenerate previews when a URL is injected or replaced before publishing.

• Add UI warnings or visual cues to alert users when a link has been modified after preview generation.

• Ensure that the actual destination URL is clearly visible or easily accessible to users before they click.
  

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Responsible Disclosure:

This vulnerability was discovered and responsibly reported by independent cybersecurity researcher Aiman Al-Hadhrami, in accordance with ethical disclosure standards.

It was privately disclosed through LinkedIn's bug bounty program on HackerOne on 2 July 2025 [Report ID: #3235035].

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Research Ethics & Statement:

This research was conducted under the principle of responsible disclosure.

No user data was accessed, and no harm was caused to LinkedIn infrastructure or members.

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Proof of Concept

The vulnerability report, complete with technical documentation and a demonstration video, was submitted to the LinkedIn security team.

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Conclusion

This vulnerability in the LinkedIn mobile application highlights a critical lapse in how link previews are managed — a seemingly minor UI behavior that can be weaponized for serious cyberattacks. By allowing outdated or misleading previews to persist even after the URL has been injected with a new destination, LinkedIn inadvertently opens the door to deception, phishing, and data theft at scale. In an era where trust and authenticity are constantly under threat, such flaws demand urgent attention. It is imperative that LinkedIn addresses this issue promptly by aligning its mobile behavior with industry standards, reinforcing preview validation mechanisms, and empowering users with clearer visibility into the links they engage with. Failure to act not only puts users at risk but also undermines trust in LinkedIn as a secure and professional platform.

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Aiman Al-Hadhrami – Independent Cybersecurity Researcher 

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