MediumCISA KEVExploited in the wildPublic exploit

WhatsApp linked-device synchronization authorization bypass on iOS and macOS

IdentifiersCVE-2025-55177CWE-863· Incorrect Authorization

CVE-2025-55177 is an incomplete authorization flaw in linked-device synchronization message handling in WhatsApp for iOS prior to 2.25.21.73, WhatsApp Business for iOS prior to 2.25.21.78, and WhatsApp for Mac prior to 2.25.21.78. According to the provided content, insufficient authorization checks on linked-device synchronization messages could allow an unrelated user to cause a target device to process content from an arbitrary URL. The issue affects Apple-platform WhatsApp clients and has been described as enabling unauthorized triggering of content processing through the linked-device sync mechanism. The content further states that WhatsApp assessed this vulnerability may have been exploited in the wild as part of a sophisticated attack chain with Apple ImageIO vulnerability CVE-2025-43300.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation could allow an attacker to trigger processing of attacker-controlled content from arbitrary URLs on a victim’s device without normal authorization. Based on the provided reporting, when chained with CVE-2025-43300 on Apple platforms, this could contribute to a zero-click compromise path used in targeted spyware operations. Reported downstream effects in the chain include unauthorized access to WhatsApp sessions, extraction of cryptographic session material, establishment of a rogue parallel WhatsApp client tied to the victim account without visible linked-device artifacts, and use of the victim account for fraudulent or malicious messaging.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by updating the underlying Apple OS to a version that fixes CVE-2025-43300, limiting use of vulnerable WhatsApp clients on affected Apple devices, and treating suspicious account behavior as potential compromise. The provided content also recommends reinstalling WhatsApp, re-authenticating on a clean device, enabling chat lock protections, and verifying suspicious financial requests out-of-band by phone. These are compensating measures only and do not replace upgrading to patched WhatsApp builds.

Remediation

Patch, then assume compromise.

Upgrade to fixed versions: WhatsApp for iOS 2.25.21.73 or later, WhatsApp Business for iOS 2.25.21.78 or later, and WhatsApp for Mac 2.25.21.78 or later. Because the content indicates exploitation in conjunction with an Apple OS vulnerability, affected users should also apply the relevant Apple security updates that address CVE-2025-43300. Where compromise is suspected, the provided content recommends reinstalling WhatsApp and re-authenticating the account on a clean, fully updated device to invalidate attacker access.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Meta PlatformsWhatsappapplication

Meta PlatformsWhatsapp Businessapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

139 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

139 SOURCESView more in app

cyber security newsNews

May 27, 2026

New 0-Click WhatsApp Account Takeover Attack Targeting iOS 16 Users

A WhatsApp linked-device synchronization vulnerability affecting iOS versions below 16.7.12 that can be used in a zero-click account takeover chain to establish a rogue WhatsApp client without alerting the victim.

scworldNews

May 26, 2026

Zero-click attack hijacks WhatsApp accounts on iOS 16 | brief | SC Media

A potentially involved iOS 16 vulnerability reportedly linked to the same zero-click WhatsApp account hijacking campaign, though its exact role is described as uncertain.

infosec writeupsNews

Apr 2, 2026

Reverse Engineering a WhatsApp 0-Click Vulnerability: A Deep Dive into CVE-2025-43300 | by Krishna Kumar | Apr, 2026 | InfoSec Write-ups

A WhatsApp-specific vulnerability that, when chained with CVE-2025-43300, enables a zero-click exploit.

cloudatg insightsNews

Feb 13, 2026

AI Development & Software Engineering | CloudATG

A WhatsApp vulnerability affecting iOS and macOS clients, described as a zero-click issue and potentially exploited in the wild.

+21 more in the timeline

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware4

Malware families riding this exploit, with evidence and IOCs.

Detection signatures2

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity114

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2025-55177

NVD

nvd.nist.gov/vuln/detail/CVE-2025-55177

MITRE CWE · CWE-863

Incorrect Authorization

Vendor Advisory

facebook.com/security/advisories/cve-2025-55177

Vendor Advisory

whatsapp.com/security/advisories/2025

US Government Resource

cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-55177