CVE-2026-39908
OpenBullet2 0.3.2 NTLMv2 Hash Disclosure via UNC Path Proxy Source
Description
OpenBullet2 through version 0.3.2 on Windows contains a credential disclosure vulnerability that allows remote attackers to capture the NTLMv2 hash of the process user by configuring a job proxy source with a UNC path pointing to an attacker-controlled server. When the job starts, the application attempts to load proxies from the UNC path, triggering an SMB authentication attempt that discloses the NTLMv2 hash, which can then be relayed or cracked offline.
INFO
Published Date :
June 8, 2026, 5:16 p.m.
Last Modified :
July 23, 2026, 7:10 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update OpenBullet2 to version 0.3.3 or later.
- Configure job proxy sources carefully.
- Avoid using UNC paths for proxy sources.
- Monitor network traffic for suspicious SMB connections.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-39908.
| URL | Resource |
|---|---|
| https://hackernoon.com/one-empty-header-to-admin-how-an-auth-bypass-breaks-openbullet2 | |
| https://www.vulncheck.com/advisories/openbullet2-ntlmv2-hash-disclosure-via-unc-path-proxy-source |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-39908 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-39908
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-39908 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-39908 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 23, 2026
Action Type Old Value New Value Added Translation Title: OpenBullet2 de openbullet, Description: OpenBullet2 hasta la versión 0.3.2 en Windows contiene una vulnerabilidad de divulgación de credenciales que permite a atacantes remotos capturar el hash NTLMv2 del usuario del proceso al configurar una fuente de proxy de trabajo con una ruta UNC que apunta a un servidor controlado por el atacante. Cuando el trabajo se inicia, la aplicación intenta cargar proxies desde la ruta UNC, desencadenando un intento de autenticación SMB que divulga el hash NTLMv2, el cual puede ser luego retransmitido o descifrado sin conexión. -
CVE Modified by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://github.com/openbullet/openbullet2', 'vendor': 'openbullet', 'product': 'openbullet2', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '0.3.2'}], 'defaultStatus': 'affected'}] [{'repo': 'https://github.com/openbullet/openbullet2', 'vendor': 'openbullet', 'product': 'openbullet2', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '0.3.2'}], 'packageURL': 'pkg:github/openbullet/openbullet2', 'defaultStatus': 'affected'}] -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/openbullet/openbullet2', 'vendor': 'openbullet', 'product': 'openbullet2', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '0.3.2'}], 'defaultStatus': 'affected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-39908', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-08T18:06:32.903409Z'} -
New CVE Received by [email protected]
Jun. 08, 2026
Action Type Old Value New Value Added Description OpenBullet2 through version 0.3.2 on Windows contains a credential disclosure vulnerability that allows remote attackers to capture the NTLMv2 hash of the process user by configuring a job proxy source with a UNC path pointing to an attacker-controlled server. When the job starts, the application attempts to load proxies from the UNC path, triggering an SMB authentication attempt that discloses the NTLMv2 hash, which can then be relayed or cracked offline. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Added CWE CWE-522 Added Reference https://hackernoon.com/one-empty-header-to-admin-how-an-auth-bypass-breaks-openbullet2 Added Reference https://www.vulncheck.com/advisories/openbullet2-ntlmv2-hash-disclosure-via-unc-path-proxy-source