ZDI-26-622: Microsoft Windows IKEv2 AES-GCM Decryption Integer Underflow Remote Code Execution Vulnerability
ZDI disclosed CVE-2026-50696, a CVSS 8.1 integer underflow in Windows IKEv2 AES-GCM decryption enabling unauthenticated remote code execution on specific IPsec configurations.
The Zero Day Initiative published ZDI-26-622 describing a remote code execution vulnerability in Microsoft Windows' IKEv2 AES-GCM decryption path, caused by an integer underflow. Authentication is not required for exploitation, but only systems using specific IPsec configurations are affected. ZDI assigned the vulnerability a CVSS score of 8.1 and the identifier CVE-2026-50696.
Zero Day Initiative — CVE-2026-33824: Remote Code Execution in Windows ...
ZDI details CVE-2026-33824, a double-free in Windows IKEv2 fragment reassembly enabling unauthenticated remote code execution as SYSTEM on Windows.
Zero Day Initiative published technical analysis of CVE-2026-33824, a double-free in the Windows IKE Extension (ikeext.dll) caused by improper ownership handling of a heap blob pointer during IKEv2 fragment reassembly in IkeReinjectReassembledPacket(). A remote unauthenticated attacker can send a crafted IKE_SA_INIT message with a Security Realm Vendor ID followed by fragmented IKE_AUTH payloads to trigger the double free. Successful exploitation could yield arbitrary code execution under the IKEEXT service context (SYSTEM). ZDI also provided IDS detection guidance correlating the two-packet sequence on UDP ports 500 and 4500.
Cisco ASA and FTD Flaw Exploited in the Wild Can Trigger Remote DoS
Cisco warns actively exploited flaw CVE-2026-20349 lets unauthenticated attackers crash ASA and FTD firewalls via SSL VPN; CISA added it to KEV.
Cisco fixed CVE-2026-20349 (CVSS 8.6) in Secure Firewall ASA and FTD software, insufficient error checking in HTTP request processing that lets unauthenticated remote attackers force device reloads via crafted requests to the Remote Access SSL VPN service. Hotfixes cover ASA 9.16 through 9.24 and FTD 7.0 through 10.0, and there are no workarounds; Cisco confirmed active exploitation earlier in August but did not name the actor or targets. The flaw was found during internal security testing. CISA added it to the KEV catalog, requiring federal civilian agencies to patch by August 14, 2026.
CISA: WatchGuard RCE flaw now exploited in ransomware attacks
CISA confirms ransomware gangs are exploiting critical unauthenticated RCE CVE-2025-14733 in WatchGuard Firebox firewalls, with roughly 9,000 devices still unpatched.
CVE-2025-14733 is an out-of-bounds write in WatchGuard Fireware OS allowing unauthenticated remote code execution, exploitable on firewalls configured for IKEv2 VPN and potentially even after the configuration was deleted if a static branch-office VPN peer remains. WatchGuard released patches in December and confirmed in-the-wild exploitation; Shadowserver found over 115,000 exposed Fireboxes at the time, with nearly 9,000 still unpatched after nine months. CISA added the flaw to its Known Exploited Vulnerabilities catalog in December under BOD 22-01 and on Thursday confirmed ransomware gangs are now exploiting it, without providing campaign details. WatchGuard serves more than 250,000 small and mid-sized companies through 17,000+ security resellers and service providers.
OpenSSL’s new alpha build speeds up post-quantum crypto
OpenSSL 4.1.0 alpha1 adds DTLS 1.3 support and speeds up ML-DSA and ML-KEM post-quantum operations across several architectures.
The OpenSSL project released the first alpha of OpenSSL 4.1.0, months before general availability. The build adds DTLS 1.3 (RFC 9147) to secure UDP-based traffic such as VPNs, video calls and IoT, and includes optimized ML-DSA and ML-KEM operations for ppc64le, s390x and x86_64 plus AVX-512 acceleration for SHAKE hashing and AES-CBC decryption. Breaking changes include a new Net::Curl::Easy dependency for tsget, dropped Windows-on-Itanium and Windows CE support, and replacement of the no-ecdsa/no-ecdh Configure options with no-ec. It also adds GREASE support (RFC 8701), a DTLS mode for the SSL listener API, IKEv2 KDF support, and initial Elbrus2000 processor architecture support.
Cisco fixes vulnerability exploited to DoS its firewalls (CVE-2026-20349)
Cisco patches CVE-2026-20349, a high-severity unauthenticated DoS in ASA and FTD VPN services now added to CISA's KEV.
CVE-2026-20349 affects the Remote Access SSL VPN service in Cisco Secure Firewall ASA and FTD software, where specially crafted unauthenticated HTTP requests can cause appliances to reload, creating a denial of service. Cisco confirmed active exploitation observed in August 2026 and released hot fixes for ASA versions 9.16 through 9.24 and FTD versions 7.0 through 10.0. The flaw was added to CISA's Known Exploited Vulnerabilities catalog with a remediation deadline of August 14, 2026 for US civilian federal agencies. No workarounds or indicators of compromise are available.