CVE-2026-39908: OpenBullet2 0.3.2 NTLMv2 Hash Disclosure via UNC Path Proxy Source
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-04 15:41 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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.
Description quoted from the CVE record (assigned by VulnCheck, published 2026-06-08).
Weakness: Insufficiently Protected Credentials
How it can be exploited
Exploitable over the network with low attack complexity with no special attack requirements needing low privileges and no user interaction. Impact: confidentiality high, integrity none, availability none. CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: no. Technical impact: partial.
Public exploit evidence (Exploit Observer)
Exploit Observer found 1 Metasploit module naming this CVE.
See all 4 references on Exploit Observer
Live scores
- EPSS
- 0.008
low predicted chance of attack - VEDAS
- 0.111
little exploit evidence - On CISA KEV
- Not listed
- Detection rule
- No public rule yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| openbullet openbullet2 | up to and including 0.3.2 | Not stated |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
Advisories on this CVE
References
Exploit code
- https://hackernoon.com/one-empty-header-to-admin-how-an-auth-bypass-breaks-openbullet2 (technical-description, exploit)
Technical analysis and advisories
- https://www.vulncheck.com/advisories/openbullet2-ntlmv2-hash-disclosure-via-unc-path-proxy-source (third-party-advisory)
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), Exploit Observer. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
Supporting partners
