Skip to content
CVE Tracker
Back

CVE-2016-4028

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…

High7.5EPSS 0.71%
Published
Updated
Reserved
Assigned by
mitre

Description

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.

Scores

CVSS scores of CVE-2016-4028, by who scored it
Scored byCVSSScoreVector
NVDNVD · Modified3.0High7.5CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
0.71% · top 47% of all CVEs (2 Nov 2026)

Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

Affected products

  • n/a

    • affected n/a

References (2)

Sources

The same CVE in the primary databases and aggregators, to check against.

Record last updated .