CVE-2026-76461: Cisco Secure Email Gateway

Should you act?

Exploited: patch now if you run it

CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

Yes, if you run Cisco Secure Email Gateway. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-09-14, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-09-17; treat that as the outer limit, not the target.
EPSS 29.5%, percentile 98: FIRST’s model estimates a 29.5% chance of exploitation activity in the next 30 days, higher than 98% of all scored CVEs (very high). EPSS is a probability, not a verdict.
Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
Editorial verdict: Act now. Cisco Secure Email Gateway: Two Exploited Root RCE Bugs — Every on-premises Secure Email Gateway below 15.5.5-014 or 16.5.0-780 can be rooted by an email and both bugs are exploited: upgrade now, and check for compromise before and after, because attackers can wipe local evidence.

What it is

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’s summary

Cisco AsyncOS software for Cisco Secure Email Gateway (SEG) contains a SQL injection vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary commands with root privileges on the underlying operating system.

Weakness type: CWE-89.

Product: Cisco Secure Email Gateway · Assigned by: cisco · Published: 2026-09-14

Affected and fixed versions

Vendor	Product	Affected versions (per CVE record)
Cisco	Cisco Secure Email	14.0.0-698, 13.5.1-277, 13.0.0-392, 14.2.0-620, 13.0.5-007, 13.5.4-038, 14.2.1-020, 14.3.0-032, 15.0.0-104, 15.0.1-030, 15.5.0-048, 15.5.1-055

Severity scores

Scored by	CVSS	Score	Vector
cisco	3.1	9.8 Critical	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

Attack vector: network (remotely reachable)
Attack complexity: low
Privileges required: none (no login)
User interaction: none
Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

CISA KEV: added 2026-09-14; federal due date 2026-09-17. Known ransomware use: Unknown.
CISA 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.
CISA SSVC assessment: exploitation active, automatable yes, technical impact total.
FIRST EPSS (model of 2026-10-21): 29.54% probability of exploitation activity in the next 30 days; percentile 98.

Timeline

2026-09-14 — Added to CISA’s Known Exploited Vulnerabilities catalog
2026-09-14 — CVE record published by cisco
2026-09-14 — erroneo.us brief: Cisco Secure Email Gateway: Two Exploited Root RCE Bugs
2026-09-17 — CISA remediation deadline for US federal agencies
2026-09-18 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.