What is CVE-2026-76519?

CVE-2026-76519 is Cisco Secure Email Gateway Arbitrary File Write Vulnerability. The supplied enrichment data classifies it as Path Traversal mapped to CWE-23 CWE-23.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

5 public PoC repositories reported; 2 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2026-76519 using CVSS 9.8, EPSS 0%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

No public threat actor linkage is confirmed from current sources. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVcriticalPath Traversalpublic exploit

CVE-2026-76519

CVE-2026-76519 — Cisco Secure Email Gateway Arbitrary File Write Vulnerability

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2026-76519 in CISA KEV with 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.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

A vulnerability in the Advanced Malware Protection (AMP) feature of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to write arbitrary files on the underlying operating system. This vulnerability is due to improper handling of email attachments when the file reputation service is enabled. An attacker could exploit this vulnerability by sending an email that contains a crafted attachment through an affected device. A successful exploit could allow the attacker to write arbitrary files and execute commands with root privileges on the underlying operating system.

Published Oct 14, 2026Updated Oct 14, 2026Sources: NVD, Cisco (CNA), CISA, GitHub, GitHub Security Advisory, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Oct 14, 2026

EPSS

ahead of 0% of scored CVEs

Affects

Cisco

23 products listed

CVSS base

9.8

critical

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade Cisco Secure Email to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

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.

Federal deadline Oct 17, 2026 — in 2 days

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
Cisco	Cisco Secure Email	14.0.0-698	Vulnerable
Cisco	Cisco Secure Email	13.5.1-277	Vulnerable
Cisco	Cisco Secure Email	13.0.0-392	Vulnerable
Cisco	Cisco Secure Email	14.2.0-620	Vulnerable
Cisco	Cisco Secure Email	13.0.5-007	Vulnerable
Cisco	Cisco Secure Email	13.5.4-038	Vulnerable
Cisco	Cisco Secure Email	14.2.1-020	Vulnerable
Cisco	Cisco Secure Email	14.3.0-032	Vulnerable
Cisco	Cisco Secure Email	15.0.0-104	Vulnerable
Cisco	Cisco Secure Email	15.0.1-030	Vulnerable
Cisco	Cisco Secure Email	15.5.0-048	Vulnerable
Cisco	Cisco Secure Email	15.5.1-055	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
9.8	CVSS 3.1	critical	3.9	5.9	Cisco (CNA), GHSA

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

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-23 · Relative Path Traversal

Execute Unauthorized Code or Commands
Modify Files or Directories
Read Files or Directories
DoS: Crash, Exit, or Restart

Mitigation: Assume all input is malicious. Use an accept known good input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, boat may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as red or blue. Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single . character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as / to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434. Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering / is insufficient protection if the filesystem also supports the use of as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if ../ sequences are removed from the .../...// string in a sequential fashion, two instances of ../ would be removed from the original string, but the remaining characters would still form the ../ string.

Weakness & attack patterns

CWE-23

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

CAPEC-139 · Relative Path TraversalCAPEC-76 · Manipulating Web Input to File System Calls

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Oct 14, 2026

Federal deadline

Oct 17, 2026

in 2 days

Ransomware use

Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

2 of the 5 sampled are weaponized

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Prioritize edge telemetry for network-reachable Cisco Secure Email.
Monitor for scanner or exploit-pattern traffic after 5 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added to CISA KEV catalog
Oct 14, 2026 · CISA
Added · CVSS 3.1 9.8 (AV:N)
Oct 14, 2026 · NVD
Initial · CVE published
Oct 14, 2026 · NVD
Added · GHSA-6rc3-jwq8-jm3v published (critical)
Oct 14, 2026 · GitHub Security Advisory
CVE published by MITRE.
Oct 14, 2026 · SOCRadar CTI

Source activity

Readings a source repeats on a schedule, counted rather than listed.

1×CVE modified by NIST: CISA KEV details updated.Oct 14, 2026 · SOCRadar CTI

References

6 on the record

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-afw-zqYJkjxp
Vendor Advisory, Mitre, NIST
www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-76519
US Government Resource, NIST
nvd.nist.gov/vuln/detail/CVE-2026-76519
NVD, Vendor Advisory
github.com/advisories/GHSA-6rc3-jwq8-jm3v
Exploit, Third Party Advisory
www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
US Government Resource
www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
US Government Resource

Elsewhere on this site

Ciscoevery CVE for this vendor
October 2026what else CISA listed
Path Traversalsame class
CWE-23other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2026-76519 is Cisco Secure Email Gateway Arbitrary File Write Vulnerability, a critical vulnerability affecting Cisco Secure Email from Cisco. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 5 public PoC repositories reported; 2 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.8 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.