CVE-2026-39908
CVE-2026-39908 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-522.
Key facts
- Severity: Medium (CVSS 3.x base score 6.5)
- CVSS v4: 7.1
- EPSS exploit prediction: 0% (23rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-35133
- Weakness: CWE-522
- Published:
- Last modified:
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2026-39908?
- CVE-2026-39908 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
- Is CVE-2026-39908 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-39908?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-39908 have an EU (EUVD) identifier?
- Yes. CVE-2026-39908 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-35133.
- When was CVE-2026-39908 published?
- CVE-2026-39908 was published on 2026-06-08 and last updated on 2026-06-17.
References
- 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
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