VulnerabilityPublished 14 Sep 2026Updated 16 Sep 2026

CVE-2026-76442: Cisco Secure Email · Improper Validation of Specified Quantity in Input

Affects Cisco Secure EmailSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 14 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
CiscoCisco Secure Email	Affected 13.0.0-392 – 16.5.0-780 24 affected builds	Fixed in–
CiscoCisco Secure Email and Web Manager	Affected 12.8.1-002 – 16.5.0-429 31 affected builds	Fixed in–

AI-suggested

Cisco has released software hardening updates that address CVE-2026-76442. Users should apply the relevant patches or upgrade to fixed versions as provided by Cisco. Since this is not a cloud service, remediation depends on customer action. Patch status is confirmed by Cisco's internal review and release of updated software versions.

Description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Email Gateway and Cisco Secure Email and Web Manager engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76442 are related to issues with improper validation of specified quantity in input that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-1284.

Impact

The vulnerability allows an unauthenticated attacker to cause denial of service on affected Cisco Secure Email systems by exploiting improper input validation. There is no impact on confidentiality or integrity. No known active exploitation has been reported.

Summary

CVE-2026-76442 involves improper validation of specified quantity in input within Cisco Secure Email products, categorized under CWE-1284. This vulnerability can lead to denial of service conditions. It affects numerous explicit versions of Cisco Secure Email as listed. The CVSS 3.1 score is 7.5 (high), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and an impact limited to availability. Cisco has conducted an internal security review and issued software hardening releases to address this and other vulnerabilities.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 22 Sep 2026, 01:00 UTC

Technical details

References

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