Cisco AsyncOS Software for Cisco Secure Email Gateway contains a SQL injection flaw (CWE-89) in its email parsing logic, caused by insufficient validation of message content. An unauthenticated, remote attacker can trigger it simply by sending a crafted email containing malicious SQL statements through an affected gateway, with no user interaction required. Successful exploitation allows arbitrary SQL execution that escalates to arbitrary operating-system command execution with root privileges, fully compromising the appliance and all mail flowing through it. Any organization running an affected version of Cisco Secure Email Gateway is impacted, and because these appliances sit on the inbound mail path they are inherently reachable over the network. There is no known public proof-of-concept, the flaw is not on the CISA KEV list, and no in-the-wild exploitation has been reported to date, though the CVSS 9.8 rating makes patching urgent.
What to do: Upgrade to the fixed AsyncOS release listed in the corresponding Cisco PSIRT advisory as soon as possible, since the flaw is unauthenticated, requires no user interaction, and yields root. Until patched, apply any Cisco-documented workarounds and tightly restrict which hosts can submit mail to the gateway where operationally feasible. Review mail and system logs on these appliances for anomalies such as SQL errors in parsing, unexpected processes, or unexplained outbound connections that could indicate exploitation attempts.
large≈ tens of thousands of gateway deployments (order of 10,000–50,000 appliances) — Cisco Secure Email Gateway appliances are enterprise mail-security gateways that are internet-facing by design (they receive inbound MX traffic), and public scan engines typically show tens of thousands of Cisco email-security hosts…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description
A vulnerability in the email parsing of Cisco AsyncOS Software for Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to execute arbitrary commands with root privileges on the underlying operating system. This vulnerability is due to insufficient validation in the email parsing logic. An attacker could exploit this vulnerability by sending a crafted email message that contains malicious SQL statements through an affected device. A successful exploit could allow the attacker to execute arbitrary SQL statements, leading to command execution with root privileges on the underlying operating system.
CISA Known Exploited Vulnerability
Affected
Cisco Secure Email Gateway
Required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Cisco Secure Email Gateway zero-day CVE-2026-76461 (CVSS 9.8) is actively exploited for root command execution; CISA added it to KEV.
Cisco disclosed critical zero-day CVE-2026-76461 (CVSS 9.8) in Secure Email Gateway, remotely exploitable without authentication via crafted emails containing malicious SQL statements, leading to arbitrary command execution with root privileges. The flaw affects physical and virtual appliances regardless of configuration and has no workarounds. Cisco PSIRT confirmed active exploitation, and CISA added the CVE to its KEV catalog on September 14 with a federal remediation deadline of September 17. Admins should review mail_logs for suspicious SQL statements such as 'COPY.*TO PROGRAM'.
Actively exploited Cisco Secure Email Gateway zero-day CVE-2026-76461 lets crafted emails trigger SQL injection and root command execution; CISA added it to KEV.
Cisco released emergency patches for CVE-2026-76461, a critical SQL injection in Secure Email Gateway (physical and virtual) caused by insufficient validation in email parsing. Sending a crafted email with malicious SQL statements can yield arbitrary command execution with root privileges. Cisco was aware of active exploitation before the fixes, and CISA added the flaw to its KEV catalog; patched AsyncOS releases are 15.5.5-0141, 16.0.4-3021, and 16.5.0-780. Because successful exploits grant root, Cisco warns logs may be tampered with and advises checking external firewall/network logs and rebuilding virtual appliances with rotated credentials.
Attackers actively exploit critical Cisco Secure Email Gateway flaw CVE-2026-76461, turning a malicious email into unauthenticated root access.
Cisco Secure Email Gateway appliances are being actively exploited via CVE-2026-76461, a CVSS 9.8 AsyncOS flaw requiring no authentication—a crafted email can yield root command execution with no workarounds. Cisco's PSIRT became aware of active exploitation in September; some Secure Email Cloud customers showed indicators of compromise and all cloud devices were upgraded to AsyncOS 16.5.0-780. The bug is in CISA's KEV catalog with federal agencies ordered to remediate by September 17; Shadowserver counted 400+ exposed appliances. Fixes are available in AsyncOS 15.5.5-014, 16.0.4-302, and 16.5.0-780, and attackers with root may tamper with logs to hide activity.
Actively exploited Cisco Secure Email Gateway zero-day CVE-2026-76461 allows unauthenticated root command execution; CISA added it to KEV.
Cisco disclosed CVE-2026-76461, a zero-day in AsyncOS for Cisco Secure Email Gateway that was exploited before disclosure and lets unauthenticated remote attackers execute commands with root privileges on cloud and on-premises instances. CISA promptly added the flaw to its Known Exploited Vulnerabilities catalog, and Cisco has directly contacted cloud customers with indicators of compromise while deploying mitigations. Rapid7 and VulnCheck warn compromised gateways could enable silent email monitoring and internal pivoting from on-premises deployments.
CVE-2026-76461 is an unauthenticated SQL injection (CWE-89) in Cisco AsyncOS for Cisco Secure Email Gateway appliances, allowing remote attackers to execute arbitrary OS commands with root privileges. CISA added the flaw to the KEV catalog on September 14, 2026, requiring federal civilian agencies to apply vendor mitigations by September 17, 2026, and forensic triage under BOD 26-04. A compromised gateway could let attackers alter email security policies, access stored messages, disable logging, and pivot into enterprise networks.
Cisco Secure Email Gateway zero-day CVE-2026-76461 (CVSS 9.8) enables unauthenticated root command execution via crafted email; CISA added it to KEV.
CVE-2026-76461 is a critical SQL injection (CVSS 9.8) in Cisco AsyncOS for Secure Email Gateway allowing an unauthenticated remote attacker to execute arbitrary commands with root privileges by sending a specially crafted email through a vulnerable gateway. CISA added it to the KEV catalog on disclosure day, indicating zero-day exploitation, and Cisco PSIRT became aware of active exploitation in September 2026. No public PoC or attribution exists; fixed versions are 15.5.5-014, 16.0.4-302, and 16.5.0-780, and admins should check mail_logs for suspicious SQL statements like 'COPY.*TO PROGRAM'.
Cisco warns CVE-2026-76461 in Secure Email Gateway AsyncOS is actively exploited, letting unauthenticated attackers run root commands via crafted emails.
Cisco disclosed CVE-2026-76461, a CVSS 9.8 flaw in AsyncOS for Cisco Secure Email Gateway caused by insufficient validation in email parsing, allowing unauthenticated remote attackers to execute arbitrary SQL statements leading to root command execution. Active exploitation began in September 2026, and CISA added the flaw to its KEV catalog, requiring FCEB agencies to patch by September 17, 2026. Fixes are available in AsyncOS 15.5.5-0141, 16.0.4-302, and 16.5.0-780, with no workarounds. Cisco also contacted Secure Email Cloud customers where malicious activity was detected, and the article separately notes large-scale credential attacks on Fortinet VPN appliances generating tens of millions of authentication failures.
Cisco patches actively exploited Secure Email Gateway zero-day CVE-2026-76461 enabling unauthenticated root command execution; CISA adds it to KEV.
Cisco disclosed that a critical zero-day (CVE-2026-76461) in the email parsing logic of AsyncOS for Secure Email Gateway is being actively exploited, allowing unauthenticated remote attackers to execute arbitrary SQL statements that lead to root-level command execution on virtual and physical appliances. CISA added the flaw to its KEV catalog and ordered federal agencies to patch within three days, by September 17. Cisco also patched four other critical SEG/SEWM vulnerabilities (CVE-2026-76440, CVE-2026-76441, CVE-2026-20353, CVE-2026-76443) with no evidence of exploitation, and shared IOCs including suspicious SQL statements in mail_logs.
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…
Cisco warns attackers actively exploit zero-day CVE-2026-76461 in Secure Email Gateway, gaining unauthenticated root command execution via crafted emails.
Cisco PSIRT confirmed active in-the-wild exploitation of CVE-2026-76461 throughout September 2026, a zero-day in Secure Email Gateway AsyncOS that lets remote, unauthenticated attackers execute arbitrary commands with root privileges by sending maliciously crafted emails containing injected SQL statements. Physical appliances, virtual deployments, and Cisco Secure Email Cloud instances were affected; Cisco deployed server-side remediations for cloud tenants but on-premises admins must patch themselves. Fixes ship in AsyncOS 16.5.0-780 plus branches 16.0.4-3021 and 15.5.5-0141, and no workarounds exist.
CISA added actively exploited Cisco Secure Email Gateway zero-day CVE-2026-76461 (CVSS 9.8) to KEV; federal agencies must patch by September 17, 2026.
CISA added CVE-2026-76461 (CVSS 9.8), a critical zero-day in Cisco AsyncOS for Cisco Secure Email Gateway, to its Known Exploited Vulnerabilities catalog. The flaw stems from insufficient validation in email parsing, letting an unauthenticated remote attacker send a crafted email with malicious SQL statements to achieve arbitrary command execution with root privileges. Cisco confirmed active exploitation in the wild, notes no workarounds exist, and recommends checking mail_logs for suspicious SQL statements like 'COPY.*TO PROGRAM' on every cluster device. Under BOD 22-01, FCEB agencies must remediate by September 17, 2026.
Actively exploited zero-day SQL injection (CVE-2026-76461) in Cisco Secure Email Gateway allows unauthenticated root command execution; CISA ordered federal remediation by September 17.
Cisco confirmed attackers are exploiting zero-day CVE-2026-76461, an unauthenticated SQL injection in the email parsing logic of AsyncOS on Secure Email Gateway appliances (versions 16.5, 16.0, 15.5 and earlier) and Secure Email Cloud. Successful exploitation yields arbitrary SQL execution and root-level command execution on the underlying OS without user interaction. Cisco became aware of active exploitation in September 2025, has directly contacted affected cloud customers, and released fixed releases 15.5.5-014, 16.0.4-302, and 16.5.0-780. CISA added the flaw to its Known Exploited Vulnerabilities catalog and required federal civilian agencies to patch by September 17 and hunt for compromise.
Cisco Secure Email Gateway flaw CVE-2026-76461 enables root command execution via crafted email SQL injection and is actively exploited, added to CISA KEV.
Cisco disclosed critical vulnerability CVE-2026-76461 in Secure Email Gateway, caused by insufficient validation in email parsing logic, allowing arbitrary SQL statements that lead to root-level command execution. CISA added the flaw to its Known Exploited Vulnerabilities Catalog with a patch deadline of September 17, 2026. The bug affects all SEG deployments regardless of configuration, with fixed releases including 15.5.5-014, 16.0.4-302, and 16.5.0-780. Defenders can check mail_logs for anomalous 'COPY ... TO PROGRAM' SQL statements to detect compromise.
Cisco disclosed CVE-2026-76461, a critical SQL injection (CVSS 9.8) in Cisco Secure Email Gateway appliances running AsyncOS, letting unauthenticated remote attackers execute arbitrary commands as root via crafted emails containing malicious SQL statements. Cisco detected malicious activity and directly contacted Secure Email Cloud customers, indicating active exploitation. No workaround exists; fixed releases are AsyncOS 15.5.5-0141, 16.0.4-3021, and 16.5.0-780, with migration to 16.5.0-780 advised. Secure Email and Web Manager and Secure Web Appliance are not affected.
Canadian Cyber Centre warns actively exploited Cisco Secure Email Gateway SQL injection CVE-2026-76461 was added to CISA's KEV database.
The Canadian Centre for Cyber Security advisory AV26-921 (September 14, 2026) covers a SQL injection vulnerability in Cisco Secure Email Gateway (AsyncOS) and Secure Email and Web Manager. Affected versions include AsyncOS/Secure Email Gateway prior to 15.5.5-014, 16.0.4-302, and 16.5.0-780, and Secure Email and Web Manager prior to 15.5.5-006 and 16.5.0-429. Cisco stated CVE-2026-76461 is being actively exploited, and CISA added it to the Known Exploited Vulnerabilities database the same day. Users and administrators are urged to apply updates as they become available.
CISA added CVE-2026-76461, an actively exploited SQL injection in Cisco Secure Email Gateway, to the KEV catalog.
CISA added CVE-2026-76461, a SQL injection vulnerability in Cisco Secure Email Gateway, to its Known Exploited Vulnerabilities (KEV) Catalog based on evidence of active exploitation. BOD 26-04 requires Federal Civilian Executive Branch agencies to prioritize rapid remediation of KEV vulnerabilities on publicly exposed assets and to check whether systems were compromised before patching. CISA encourages all organizations to adopt risk-based vulnerability management and prioritize KEV remediation.