padloc: Improperly Controlled Modification of Object Prototype Attributes
CVE-2026-126570 is a high-severity improperly controlled modification of object prototype attributes vulnerability in padloc, with a CVSS 3.1 base score of 7.6 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists version 4.3.1 as the first without the flaw, so updating padloc to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update padloc to 4.3.1 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
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
- HighAdministrator-level access is required first.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- LowLimited modification of data is possible.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:H. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.0 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.6 | High | CNA (vulncheck.com) |
Official description
Padloc 4.0.0 before 4.3.1 contains a prototype pollution vulnerability that allows SCIM token holders to modify Object.prototype by sending crafted SCIM PATCH paths to ScimServer._handleScimUsersPatch(). Attackers can supply paths like __proto__.x or constructor.prototype.x passed to setPath() to pollute the shared server process, disrupting requests for all other organizations.
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
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Improperly Controlled Modification of Object Prototype Attributes vulnerabilities
- 8.2 High severity
- 8.4 High severity
- 7.1 High severity
- 8.3 High severity
- 7.2 High severity
- 7.2 High severity
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