CyberSecBulletin
CVE-2022-26662NVD status: Modified

Proteus: Improper Restriction of Recursive Entity References in DTDs

Published Updated By the CyberSecBulletin desk

CVE-2022-26662 is a high-severity improper restriction of recursive entity references in dtds vulnerability in Proteus from Tryton, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 5.0.12, 6.0.5, 6.2.2 as the first without the flaw, so updating Proteus to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.97% chance of exploitation within 30 days, higher than 81% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Proteus to 5.0.12 or 6.0.5 or 6.2.2, whichever matches your release line, or a later version.
  2. Update Trytond to 5.0.46 or 6.0.16 or 6.2.6, whichever matches your release line, or a later version.
  3. Read the advisory on bugs.tryton.org for workarounds and exact fixed builds.
  4. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
TrytonProteus5.0.0 up to, but not including, 5.0.12; 6.0.0 up to, but not including, 6.0.5; 6.2.0 up to, but not including, 6.2.25.0.12, 6.0.5, 6.2.2
TrytonTrytond5.0.0 up to, but not including, 5.0.46; 6.0.0 up to, but not including, 6.0.16; 6.2.0 up to, but not including, 6.2.65.0.46, 6.0.16, 6.2.6
DebianDebian Linux9.0; 10.0; 11.0Not stated

Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
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
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

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

Scoring systemScoreSeverityScored by
CVSS 3.17.5HighNVD
CVSS 2.05.0MediumNVD

Official description

An XML Entity Expansion (XEE) issue was discovered in Tryton Application Platform (Server) 5.x through 5.0.45, 6.x through 6.0.15, and 6.1.x and 6.2.x through 6.2.5, and Tryton Application Platform (Command Line Client (proteus)) 5.x through 5.0.11, 6.x through 6.0.4, and 6.1.x and 6.2.x through 6.2.1. An unauthenticated user can send a crafted XML-RPC message to consume all the resources of the server.

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

The underlying weakness: Improper Restriction of Recursive Entity References in DTDs

The product uses XML documents and allows their structure to be defined with a Document Type Definition (DTD), but it does not properly control the number of recursive definitions of entities.

How developers prevent this class of flaw

  • If possible, prohibit the use of DTDs or use an XML parser that limits the expansion of recursive DTD entities.
  • Before parsing XML files with associated DTDs, scan for recursive entity declarations and do not continue parsing potentially explosive content.

More Improper Restriction of Recursive Entity References in DTDs vulnerabilities (CWE-776)

Timeline

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

References

Third-party and government advisories

Recent Improper Restriction of Recursive Entity References in DTDs vulnerabilities

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