VulnerabilityPublished 17 Jun 2025

CVE-2025-6152: Steel Browser · Path Traversal

Affects Steel BrowserSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score

5.3Medium

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

EPSS: 0.6% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: Low
Vulnerable system integrity: Low
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

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

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, 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: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Vulnerable System.
Vulnerable system 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 to the Vulnerable System.
Vulnerable system 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 Vulnerable System 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 Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 17 Jun 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

Affected software

Product	Affected	Fixed in
GitHubsteel-dev/steel-browser`pkg:github/steel-dev/steel-browser`Other threats	Affected 0.1.0 – 0.1.3 4 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Apply the official patch identified by commit 7ba93a10000fb77ee01731478ef40551a27bd5b9 immediately to all affected Steel Browser instances to remediate the vulnerability.
Implement strict input validation and sanitization on the filename parameter in the file upload functionality to prevent directory traversal sequences (e.g., '..', absolute paths).
Employ least privilege principles for the Steel Browser application process, ensuring it runs with minimal filesystem permissions to limit the impact of potential exploitation.
Use containerization or sandboxing techniques to isolate the Steel Browser environment, reducing the risk of filesystem access beyond intended boundaries.
Monitor logs for suspicious file upload activities, especially those containing unusual path patterns or attempts to access sensitive directories.
Restrict access to the file upload endpoint to authenticated and authorized users where possible, even though the vulnerability does not require authentication, to reduce exposure.
Conduct regular security assessments and penetration tests focusing on file upload functionalities to detect similar vulnerabilities proactively.

Description

A vulnerability, which was classified as critical, was found in Steel Browser up to 0.1.3. This affects the function handleFileUpload of the file api/src/modules/files/files.routes.ts. The manipulation of the argument filename leads to path traversal. It is possible to initiate the attack remotely. The patch is named 7ba93a10000fb77ee01731478ef40551a27bd5b9. It is recommended to apply a patch to fix this issue.

Impact

For European organizations using Steel Browser versions 0.1.0 through 0.1.3, this vulnerability poses a risk of unauthorized file system access via path traversal during file uploads. The impact includes potential exposure of sensitive data stored on the server, unauthorized modification of files, or disruption of service if critical files are overwritten. Organizations in sectors that rely on Steel Browser for internal or customer-facing applications—such as software development firms, digital service providers, or enterprises using Steel Browser as part of their web infrastructure—may face confidentiality breaches or integrity violations. Given the medium CVSS score and the requirement for some level of privileges to exploit, the threat is moderate but should not be underestimated, especially in environments where the Steel Browser is exposed to untrusted networks or users. The absence of known exploits in the wild suggests limited active targeting currently, but the availability of a patch and public disclosure increases the risk of future exploitation attempts. European organizations with sensitive data or critical infrastructure should prioritize remediation to prevent potential lateral movement or data leakage.

References

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