CyberSecBulletin
CVE-2023-26436NVD status: Modified

OX App Suite: Deserialization of Untrusted Data

Published Updated By the CyberSecBulletin desk

CVE-2023-26436 is a high-severity deserialization of untrusted data vulnerability in OX App Suite from OX Software, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected OX App Suite versions: 7.10.6-rev7 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.25% chance of exploitation within 30 days, higher than 70% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Open-xchange Appsuite Backend to 7.10.6 or a later version.
  2. Read the advisory on documentation.open-xchange.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
OX SoftwareOX App Suite7.10.6-rev7 and earlierNot stated
Open-XchangeOpen-xchange Appsuite Backendbefore 7.10.6; 7.10.67.10.6

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
AdjacentThe attacker must be on the same local network segment.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.1HighCNA (open-xchange.com)
CVSS 3.18.8HighNVD

Official description

Attackers with access to the "documentconverterws" API were able to inject serialized Java objects, that were not properly checked during deserialization. Access to this API endpoint is restricted to local networks by default. Arbitrary code could be injected that is being executed when processing the request. A check has been introduced to restrict processing of legal and expected classes for this API. We now log a warning in case there are attempts to inject illegal classes. No publicly available exploits are known.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Deserialization of Untrusted Data

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

How developers prevent this class of flaw

  • If available, use the signing/sealing features of the programming language to assure that deserialized data has not been tainted. For example, a hash-based message authentication code (HMAC) could be used to ensure that data has not been modified.
  • When deserializing data, populate a new object rather than just deserializing. The result is that the data flows through safe input validation and that the functions are safe.
  • Explicitly define a final object() to prevent deserialization.

More Deserialization of Untrusted Data vulnerabilities (CWE-502)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in OX App Suite

All OX App Suite vulnerabilities

Recent Deserialization of Untrusted Data vulnerabilities

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