CVE-2026-39908

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.

CVSS v4.0

7.1 HIGHCVSS:4.0/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

CVSS v3.1

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

EPSS

0.31% chance of exploitation in the next 30 days, 24th percentile

Published

2026-06-08

Updated

2026-07-14

Proof-of-concept exploits (1)

• https://hackernoon.com/one-empty-header-to-admin-how-an-auth-bypass-breaks-openbullet2

References

• CVE Record
• NVD entry

Related

• CVE-2026-39907
• CVE-2026-39912
• CVE-2026-39906
• CVE-2026-3992
• CVE-2026-39904
• CVE-2026-39920