CyberSecBulletin
CVE-2022-39357NVD status: Modified

winter: Improperly Controlled Modification of Object Prototype Attributes

Published Updated By the CyberSecBulletin desk

CVE-2022-39357 is a critical-severity improperly controlled modification of object prototype attributes vulnerability in winter from Wintercms, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected winter versions: >= 1.1.8, < 1.1.10; = 1.2.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.4% chance of exploitation within 30 days, higher than 73% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of winter you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. 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
Wintercmswinter>= 1.1.8, < 1.1.10; = 1.2.0Not stated

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

Scoring systemScoreSeverityScored by
CVSS 3.18.1HighCNA (github.com)
CVSS 3.19.8CriticalNVD

Official description

Winter is a free, open-source content management system based on the Laravel PHP framework. The Snowboard framework in versions 1.1.8, 1.1.9, and 1.2.0 is vulnerable to prototype pollution in the main Snowboard class as well as its plugin loader. The 1.0 branch of Winter is not affected, as it does not contain the Snowboard framework. This issue has been patched in v1.1.10 and v1.2.1. As a workaround, one may avoid this issue by following some common security practices for JavaScript, including implementing a content security policy and auditing scripts.

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

The underlying weakness: Improperly Controlled Modification of Object Prototype Attributes

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

How developers prevent this class of flaw

  • By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
  • By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
  • When handling untrusted objects, validating using a schema can be used.

More Improperly Controlled Modification of Object Prototype Attributes vulnerabilities (CWE-1321)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in winter

All winter vulnerabilities

Recent Improperly Controlled Modification of Object Prototype Attributes vulnerabilities

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