Cisco Publishes 12 Security Advisories Fixing Critical Flaws in Catalyst SD-WAN and IOS XE
Cisco Systems released 12 new security advisories on August 5, 2026, disclosing a total of 23 vulnerabilities across multiple products including Cisco Catalyst SD-WAN Software and Cisco IOS XE Software.
Two of the advisories were rated Critical, the highest severity level. The Cisco Catalyst SD-WAN Software advisory covers five vulnerabilities. The most severe include input validation issues tracked as CVE-2026-20303, access control bypass CVE-2026-20304, and link interpretation problems CVE-2026-20310, all carrying a CVSSv3.1 base score of 9.9.
The Cisco IOS XE Software advisory addresses seven flaws. Notable entries are improper neutralization of special elements CVE-2026-20272 (CVSS 9.8) and access control weaknesses CVE-2026-20267 (CVSS 9.0), plus five additional issues rated 8.6.
Further advisories cover argument injection in Cisco Integrated Management Controller, denial-of-service conditions in Extensible Messaging Client Protocol and SNMP implementations, information disclosure in Cisco Catalyst SD-WAN Manager and RoomOS, and firewall rule bypass in Cisco Terminal Services Agent.
Links to the full advisories and hardening releases are available on the Cisco security portal. Administrators should prioritize patching to prevent remote code execution and denial-of-service attacks.
Related articles
How Modern API Attacks Abuse Legitimate Functionality Instead of Exploiting Vulnerabilities
Traditional API incidents once centered on authorization errors, access control issues, SQL injections, and known vulnerability exploitation. Today, many attacks on APIs no longer require finding code flaws; attackers simply use documented methods, valid authorization, and correct parameters at unexpected scale or timing. NGENIX security teams observe three main behavioral patterns: Burst attacks that overload resource-heavy endpoints, Shortwave attacks that exploit race conditions through timed parallel requests, and Carpet Bombing that distributes activity across dozens of endpoints for reconnaissance or scalping. These techniques often bypass WAF because each individual request appears fully compliant with API specifications. Protection is shifting toward behavioral analysis, sliding-window rate limiting, and monitoring of overall client behavior rather than single-request signatures. Real-world cases include sudden catalog scraping during contests and mass reservation of airline seats without purchases, leading to degraded service for legitimate users.
Critical Vulnerabilities Patched in WHMCS Billing Software for Hosting Providers
WebPros International has disclosed two serious vulnerabilities in its WHMCS billing management platform used by hosting and cloud service providers. CVE-2026-67399 allows unauthenticated remote code execution through unsafe deserialization of untrusted data under specific conditions, potentially compromising the entire server environment and associated data. CVE-2026-67398 affects the 2CheckOut payment gateway module and stems from missing authorization checks, enabling attackers to retrieve sensitive customer information including names, addresses, emails, and phone numbers without authentication. HackerOne assigned CVSS v4.0 scores of 9.3 (Critical) to the first issue and 8.2 (High) to the second. WebPros released fixed versions WHMCS 9.0.8 and 8.13.7, and recommended disabling the 2CheckOut module as a temporary mitigation for the second flaw.
Cisco Releases Critical Patches for Exploited SQL Injection Flaw in Secure Email Gateway
Cisco Systems has issued security updates for Cisco Secure Email Gateway to address a critical SQL injection vulnerability tracked as CVE-2026-76461. The flaw stems from insufficient input validation during email parsing and allows unauthenticated remote attackers to execute arbitrary SQL commands. Successful exploitation can lead to root-level access on the underlying operating system, enabling full command execution. The vulnerability carries a CVSSv3.1 base score of 9.8 and is rated Critical. Cisco confirmed active exploitation of the issue in September 2026. Recommended fixes include upgrading to versions 16.5.0-780, 16.0.4-3021, or 15.5.5-0141, with strong preference given to the newest release.
Telegram Desktop HTML Export Flaw Allowed Stealthy JavaScript Injection into Chat History
Researchers at ExPatch identified a vulnerability in Telegram Desktop that enabled attackers to embed malicious JavaScript into exported HTML chat histories without user detection. The flaw stemmed from insufficient sanitization of button captions added by bots, allowing hidden scripts to execute when the HTML file was opened in a browser. Malicious messages could be forwarded into chats and remain dormant until export, potentially exfiltrating messages, sender names, and timestamps to attacker servers. The issue affected versions 4.15.1 through 6.9.3, with fixes released in beta 6.9.4 and stable version 7.0.1 on July 14. No in-the-wild exploitation was observed, though the attack required specific conditions including an unpatched export and JavaScript-enabled browser. Users are advised to re-export chats after updating or open old files with JavaScript disabled.