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WeChat Worm Can Hijack Accounts Without Victims Answering Calls

Researchers demoed WeWorm, a zero-click WeChat worm hijacking accounts via incoming VoIP calls using a memory corruption flaw; Tencent patched it in August.

Researchers at Calif exploited a memory corruption bug in WeChat's VoIP system, taking over accounts through an incoming call even if the victim never answers or touches the phone. The attacker must already be a WeChat contact, but compromising a friend's account bypasses this, and chained calls spread the worm across three Android and iOS test phones in seconds. Tencent fixed the flaw in Android 8.0.77 and iOS 8.0.76 released in August, and researchers found no evidence of real-world exploitation. WeChat and Weixin reported 1.418 billion combined monthly active users at the end of 2025.

Security Affairs · 7d agoExploit / PoC

Chinese Hackers Exploit Critical Tencent Software Flaw for One-Click Code Execution

China-linked UNC3569 actively exploited critical Sogou Input Method flaw CVE-2026-51990 for one-click system-level code execution, deploying the GrayRabbit backdoor.

Gen Threat Labs reports that China-linked threat actor UNC3569, possibly tied to contractor i-SOON, exploited critical CVE-2026-51990 in Tencent's Sogou Input Method, a Windows IME used by hundreds of millions, via crafted sgbiz URLs. The chain combines unvalidated command-line argument injection, unrestricted URL navigation, and an un-sandboxed Chromium 80 engine missing roughly six years of security patches. The exploit gives system-level code execution and was used to deploy the GrayRabbit backdoor, which provides a reverse shell, plugin loading, file upload to C2, and system info collection, and has appeared in UNC3569 intrusions since at least 2021. Tencent patched the issue in version 16.3.0.3498 via automatic update, but the outdated Chromium configuration reportedly remained unchanged as of September 10.

SecurityWeek · 1d agoExploit / PoC in the wild 2 sourcesCVE-2026-519901· 1 read

WeChat worm could pwn a friend before they even answered the call

Calif researchers demoed WeWorm, a zero-click WeChat VoIP memory-corruption worm enabling account takeover; Tencent patched it August 21.

Security firm Calif found a memory corruption bug in WeChat's VoIP stack that let a trusted contact take over a user's account simply by calling them, without the call being answered. The demo worm then called the victim's contacts to self-propagate across iOS and Android; declining the call prevented infection. Tencent pushed fixes on August 21, and Calif said chaining the bug with other Android and iOS flaws could yield full device control. Calif used AI to find the vulnerability and build its first RCE exploit in about two days.

The Register · Securityupdated · 5d agofirst · 6d agoExploit / PoC 3 sources

WeWorm – First 0-Click Worm Spreading Through WeChat Calls Across iOS and Android

Researchers demonstrated WeWorm, a zero-click worm exploiting a memory-corruption flaw in WeChat's VoIP stack to spread via calls across iOS and Android.

Security firm Calif published WeWorm, a proof-of-concept zero-click worm exploiting a memory-corruption bug in WeChat's VoIP stack to spread through voice calls on iOS and Android without the victim answering. The demo chained a Pixel 10a, an iPhone 17e, and a second Pixel 10a, compromising each device while the call was still ringing and giving full control of the WeChat account. The attacker must already be on the victim's friend list, but compromised contacts become the propagation layer across a platform with over 1.4 billion monthly users. Calif reported the bug to Tencent in July 2026, and Tencent has since mitigated it; full technical details are withheld for a later conference presentation.

Cyber Security News · 7d agoExploit / PoC

One Click on a Malicious Link Lets Hackers Backdoor Sogou Input Method Users

Actively exploited one-click flaw in Sogou Input Method (CVE-2026-51990) let UNC3569 deploy the GRAYRABBIT espionage backdoor on Windows.

Gen Digital researchers found three weaknesses in Sogou Input Method's sgbiz protocol handler that chain into a one-click RCE running with the signed-in user's permissions. UNC3569 used the chain in an active intrusion, leveraging an unsandboxed Chromium 80 embedded browser, the known V8 flaw CVE-2021-38003, and DLL sideloading via 7-Zip to deploy the GRAYRABBIT backdoor. Tencent fixed the issue in version 16.3.0.3498 within 12 days of disclosure; Sogou is used by hundreds of millions of people, mainly in China.

Week in review: Linux rootkit deployed on F5 BIG-IP APM devices, Cisco FMC bugs exploited

Weekly roundup: Cisco FMC and N-able N-central zero-days exploited in the wild, MikroTik RouterOS hijacks, Microsoft Patch Tuesday ships two exploited zero-days.

State-sponsored and financially-motivated attackers are actively exploiting CVE-2026-20079, a critical authentication bypass in Cisco Secure Firewall Management Center (FMC), alongside CVE-2026-20316. N-able issued an emergency hotfix for CVE-2026-86218, a critical pre-auth RCE in the N-central RMM platform exploited in the wild. CERT Polska disclosed six RouterOS vulnerabilities being chained to hijack internet-exposed MikroTik devices. Microsoft's September 2026 Patch Tuesday shipped a record patch count including two zero-days, while roughly 67,000 Trezor customers faced phishing after a shipping-partner breach and researchers privately disclosed a zero-click WeChat worm to Tencent.

Help Net Security · 2d agoExploit / PoC in the wildCVE-2026-20079CVE-2026-20316CVE-2026-862182· 1 read

Root RCE Zero-Day in Cisco Secure Email Gateway Under Active Exploitation

Cisco warned customers on Monday that a zero-day vulnerability affecting Secure Email Gateway appliances has been exploited in the wild. The vulnerability is identified as CVE-2026-76461 and has a CVSS score of 9.8. Cisco describes it as an email parsing issue in AsyncOS software that can be exploited remotely and without authentication to execute arbitrary commands on the underlying operating…

SecurityWeekupdated · 2h agofirst · 17h agoExploit / PoC in the wild 15 sourcesCVE-2026-76461CVE-2025-20393CVE-2026-20079+1 CVEs

Weekly Cybersecurity Newsletter Bulletin – Microsoft 0-day, FortiOS, PAN-OS Flaw, Revolut Data Breach, and 20+ Stories

Weekly roundup: Microsoft patches 973 flaws including two actively exploited zero-days; FortiOS CAPWAP flaw deploys PivotC2 RAT; PAN-OS root RCE disclosed.

Microsoft's September 2026 Patch Tuesday fixed 973 vulnerabilities, including two zero-days under active exploitation: CVE-2026-85880 (Windows ALPC) and CVE-2026-81963 (Windows Update Stack), both elevation-of-privilege bugs. SOCRadar reported active exploitation of CVE-2025-25249 (CVSS 9.8) in FortiOS CAPWAP, deploying a Node.js RAT called PivotC2 that exfiltrates Exchange mailboxes to Wasabi cloud storage; 178 devices were compromised out of 30,000 scanned IPs, attributed to a Russian-speaking financially motivated group. Palo Alto disclosed CVE-2026-0310, a 9.2-rated buffer overflow enabling root code execution on PA-Series firewalls, and Fortinet disclosed CVE-2026-84393, a ZTNA certificate validation MITM flaw. Cyera also revealed CVE-2026-6471 ('PostGREShell'), a 12-year-old PostgreSQL logical-decoding flaw allowing code execution via REPLICATION-privileged accounts.