VulnerabilityPublished 29 Apr 2026Updated 30 Apr 2026

CVE-2025-50328: B1FREE · CVE-2025-50328 is a

Affects B1FREESource CVE Database V5

Not known to be exploited · CVSS 7.3 High.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

7.3High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% 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:L/I:L/A:L

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

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: 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 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 29 Apr 2026
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
GitHubmath69b/B1FREE`pkg:github/math69b/B1FREE`Other threats	Affected =1.5.86	Fixed in–

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

AI-suggested

Until an official fix is available, users should exercise caution when extracting archives downloaded from the internet using B1 Free Archiver. Consider using alternative extraction tools that correctly propagate the Zone.Identifier stream or manually verify the origin and safety of extracted files before execution.

Description

CVE-2025-50328 is a vulnerability in B1 Free Archiver v1.5.86 where extracted files from internet-downloaded archives do not retain the Windows Mark of the Web (MotW) security attribute. This omission allows these files to bypass Windows Defender SmartScreen warnings and security prompts, potentially enabling untrusted code execution without typical Windows security restrictions. The vulnerability has a high severity rating with a CVSS score of 7.3. No official patch or remediation guidance is currently available from the vendor.

Impact

Files extracted using the vulnerable B1 Free Archiver can bypass Windows security mechanisms designed to warn users about potentially unsafe files downloaded from the internet. This can lead to untrusted code execution without triggering Windows Defender SmartScreen or other security prompts, increasing the risk of malware execution and system compromise. The impact affects confidentiality, integrity, and availability at a low level but is significant due to the lack of user warnings.

Summary

The vulnerability in B1 Free Archiver v1.5.86 involves failure to propagate the 'Zone.Identifier' alternate data stream when extracting files from archives downloaded from the internet. This stream is used by Windows to mark files as originating from an untrusted source, triggering security features such as SmartScreen warnings. Without this marking, extracted files can execute without user prompts or warnings, increasing the risk of executing malicious code. The CVSS score of 7.3 reflects network attack vector, low attack complexity, no privileges or user interaction required, and impacts confidentiality, integrity, and availability at a low level.

CWE-290Authentication Bypass by Spoofing (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
OWASP Cheat Sheets
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V3.5.1 (opens in a new tab)
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
Attack patterns
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Web Services API Signature Forgery Leveraging Hash Function Extension Weakness (opens in a new tab)
Signature Spoof (opens in a new tab)
Signature Spoofing by Misrepresentation (opens in a new tab)
Session Credential Falsification through Prediction (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 7 May 2026, 02:18 UTC

WeaknessesCWE-290

Technical details

References

Community reviews

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