VulnerabilityPublished 9 Aug 2025Updated 12 Aug 2025

CVE-2025-55013: CybercentreCanada assemblyline · Relative Path Traversal

Affects CybercentreCanada assemblylineSource CVE Database V5

Not known to be exploited · CVSS 4.2 Medium · fixed in 4.6.1 : update CybercentreCanada assemblyline when convenient.

Data as of 26 Oct 2026, 11:07 UTC

CVSS 3.1 base score

4.2Medium

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.6.1

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

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

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

Attack Vector: Adjacent: The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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

AI-suggested

European organizations should take the following specific mitigation steps: 1) Upgrade all Assemblyline 4 Service Client deployments to version 4.6.1.dev138 or later, where the vulnerability is fixed. 2) Ensure that all communications between Assemblyline clients and servers are encrypted and authenticated using strong TLS configurations to prevent MITM attacks. 3) Implement strict network segmentation and access controls to limit exposure of Assemblyline servers and clients to trusted networks only. 4) Employ file system monitoring and integrity checking on systems running Assemblyline clients to detect unauthorized file writes or modifications, particularly outside expected directories. 5) Review and harden the configuration of Assemblyline deployments to minimize privileges of the service client process, reducing potential impact of arbitrary file writes. 6) Conduct regular security audits and penetration testing focusing on the Assemblyline infrastructure to identify potential weaknesses in deployment and communication security. 7) Educate security teams about the risks of path traversal vulnerabilities and the importance of validating all inputs from external services, even trusted ones. These measures go beyond generic patching advice by emphasizing secure deployment architecture, communication security, and active monitoring tailored to the Assemblyline environment.

Description

The Assemblyline 4 Service Client interfaces with the API to fetch tasks and publish the result for a service in Assemblyline 4. In versions below 4.6.1.dev138, the Assemblyline 4 Service Client (task_handler.py) accepts a SHA-256 value returned by the service server and uses it directly as a local file name.A malicious or compromised server (or any MITM that can speak to client) can return a path-traversal payload such as `../../../etc/cron.d/evil` and force the client to write the downloaded bytes to an arbitrary location on disk. This is fixed in version 4.6.1.dev138.

Impact

For European organizations, the impact of CVE-2025-55013 depends on the deployment and trust model of Assemblyline 4 within their security infrastructure. Assemblyline is used for automated malware analysis and threat intelligence, often in SOCs, CERTs, and security research environments. Exploitation could allow an attacker controlling or intercepting the Assemblyline server-client communication to write arbitrary files on the client system. This could lead to integrity compromise of the analysis environment, enabling attackers to implant backdoors, disrupt malware analysis workflows, or escalate privileges if critical system files are overwritten. Although the confidentiality impact is rated none, the integrity and availability impacts, while low, could disrupt security operations and reduce trust in threat intelligence outputs. European organizations with strict regulatory requirements for system integrity and incident response may face operational risks and compliance challenges if such a vulnerability is exploited. The medium severity rating reflects the complexity of attack (adjacent network with high complexity) and the requirement that the attacker must control or intercept the server-client communication channel. However, in environments where Assemblyline servers are exposed or communications are not properly secured (e.g., lacking TLS or vulnerable to MITM), the risk increases. The lack of known exploits in the wild suggests limited immediate threat but does not preclude targeted attacks against high-value European targets such as critical infrastructure operators, government CERTs, or large enterprises using Assemblyline for malware analysis.

CWE-23Relative Path Traversal (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.
Implementation · Input Validation
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.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
Operation · Firewall
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.3.1 (opens in a new tab)
Attack patterns
Relative Path Traversal (opens in a new tab)
Manipulating Web Input to File System Calls (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 17 Aug 2025, 01:03 UTC

WeaknessesCWE-23

Technical details

References

Community reviews

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