CVE-2016-4028 json
An issue was discovered in Open-Xchange OX Guard before 2.4.0-rev8.
published 2016-12-15 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-5034
- cvss
- 7.5
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 53%
- public exploits
- 0
- none known
Summary
An issue was discovered in Open-Xchange OX Guard before 2.4.0-rev8. OX Guard uses an authentication token to identify and transfer guest users' credentials. The OX Guard API acts as a padding oracle by responding with different error codes depending on whether the provided token matches the encryption padding. In combination with AES-CBC, this allows attackers to guess the correct padding. Attackers may run brute-forcing attacks on the content of the guest authentication token and discover user credentials. For a practical attack vector, the guest users needs to have logged in, the content of the guest user's "OxReaderID" cookie and the value of the "auth" parameter needs to be known to the attacker.
Exploit prediction
0.71% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 3.5 | AV:N/AC:M/Au:S/C:P/I:N/A:N |
Classification
- Weakness
-
- CWE-255 Credentials Management Errors
References
-
securitytracker.com
/id/1036154
vdb-entry, third-party-advisory
-
securityfocus.com
/archive/1/538732/100/0/threaded
mailing-list
Sources
- CVE List CVE-2016-4028
- NVD CVE-2016-4028
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.