CyberSecBulletin
CVE-2024-21548NVD status: Deferred

bun: Improperly Controlled Modification of Object Prototype Attributes

Published Updated By the CyberSecBulletin desk

CVE-2024-21548 is a high-severity improperly controlled modification of object prototype attributes vulnerability in bun, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 1.1.30 as the first without the flaw, so updating bun to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.67% chance of exploitation within 30 days, higher than 53% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update bun to 1.1.30 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
Bunbun0.0.12 up to, but not including, 1.1.301.1.30

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
HighSuccess depends on conditions outside the attacker's control.
Privileges required
LowA basic user account is enough.
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:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (snyk.io).

Scoring systemScoreSeverityScored by
CVSS 4.06.8MediumCNA (snyk.io)
CVSS 3.17.5HighCNA (snyk.io)

Official description

Versions of the package bun after 0.0.12 and before 1.1.30 are vulnerable to Prototype Pollution due to improper input sanitization. An attacker can exploit this vulnerability through Bun's APIs that accept objects. **Note:** This issue relates to the widely known and actively developed 'Bun' JavaScript runtime. The bun package on NPM at versions 0.0.12 and below belongs to a different and older project that happened to claim the 'bun' name in the past.

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: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improperly Controlled Modification of Object Prototype Attributes vulnerabilities

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