What is CVE-2026-104805?

CVE-2026-104805 is Mitel MiVoice Office 400 Backup Restoration Arbitrary File Write Leading to Root Code Execution. The supplied enrichment data classifies it as Path Traversal mapped to CWE-22 Path Traversal; CWE-73 CWE-73; CWE-494 CWE-494; CWE-345 CWE-345; CWE-434 Unrestricted Upload of File with Dangerous Type.

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?

Active exploitation is not confirmed from current sources for CVE-2026-104805. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

No. CVE-2026-104805 is not listed in CISA KEV in the supplied enrichment data. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

Is there a public exploit?

A public PoC is not confirmed from current sources for CVE-2026-104805. 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-2026-104805 using CVSS 8.5, 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. Prioritize based on EPSS, PoC availability, and external exposure. 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.

highPath Traversal

CVE-2026-104805

CVE-2026-104805 — Mitel MiVoice Office 400 Backup Restoration Arbitrary File Write Leading to Root Code Execution

DigitalCanion has discovered a vulnerability in the backup restoration functionality that allows an attacker with access to the configured backup repository to introduce arbitrary files into the system during restoration. The specific flaw exists within the backup restoration mechanism, which fails to properly validate the paths, file types, integrity, and authenticity of files contained within a restored TGZ archive. The application does not perform file-signature verification before extracting the archive, allowing a specially crafted backup to contain attacker-controlled files. An attacker with access to the backup SFTP or other configured repository can therefore provide a malicious TGZ archive that, when restored by the system, may place arbitrary files on the underlying Linux system. Depending on the location and permissions of the extracted files, this behavior can potentially be leveraged to achieve arbitrary code execution with root privileges and compromise the underlying virtual machine. The absence of enforced backup passwords further reduces the protection provided by the backup mechanism and may facilitate unauthorized access to the repository.

Published Oct 5, 2026Updated Oct 5, 2026Sources: NVD, Mitel (CNA), 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

Unreported

no source claims exploitation

EPSS

ahead of 0% of scored CVEs

Affects

Mitel

Mitel MiVoice Office 400

CVSS base

8.5

high

Remediation

The vendor's own words where we have them.

Upgrade Mitel MiVoice Office 400 to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

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.
Prioritize based on EPSS, PoC availability, and external exposure.
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
Mitel	Mitel MiVoice Office 400	11.0.96.0	Vulnerable

Attack characteristics

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

Scope

Attack Complexity

Low

Attack Vector

Network

Privileges Req

High

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
8.5	CVSS 4.0	high	—	—	Mitel (CNA)

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/AU:Y/R:U/V:D/RE:M/U:Amber

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-73 · External Control of File Name or Path

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

Mitigation: When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.

CWE-494 · Download of Code Without Integrity Check

Execute Unauthorized Code or Commands
Alter Execution Logic
Other

Mitigation: Perform proper forward and reverse DNS lookups to detect DNS spoofing.

Weakness & attack patterns

CWE-22Path Traversal
CWE-73
CWE-494
CWE-345
CWE-434Unrestricted Upload of File with Dangerous Type

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

CAPEC-126 · Path TraversalCAPEC-76 · Manipulating Web Input to File System CallsCAPEC-79 · Using Slashes in Alternate EncodingCAPEC-64 · Using Slashes and URL Encoding Combined to Bypass Validation LogicCAPEC-78 · Using Escaped Slashes in Alternate Encoding

T1562.003Impair Defenses: Impair Command History Logging
T1574.006Hijack Execution Flow: Dynamic Linker Hijacking
T1574.007Hijack Execution Flow: Path Interception by PATH Environment Variable

Detection

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

Prioritize edge telemetry for network-reachable Mitel MiVoice Office 400.

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 · CVSS 3.1 8.5 (AV:N)
Oct 5, 2026 · NVD
Initial · CVE published
Oct 5, 2026 · NVD
Added · GHSA-vh23-h9qx-6q3f published (high)
Oct 5, 2026 · GitHub Security Advisory
CVE published by MITRE.
Oct 5, 2026 · SOCRadar CTI

References

3 on the record

digitalcanion.com/en/security-research/#vendor=mitel&status=cna
Vendor Advisory
nvd.nist.gov/vuln/detail/CVE-2026-104805
NVD
github.com/advisories/GHSA-vh23-h9qx-6q3f
Exploit, Third Party Advisory

Elsewhere on this site

Mitelevery CVE for this vendor
Path Traversalsame class
CWE-22other 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-2026-104805 is Mitel MiVoice Office 400 Backup Restoration Arbitrary File Write Leading to Root Code Execution, a high vulnerability affecting Mitel MiVoice Office 400 from Mitel. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-104805. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-104805. 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 8.5 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.