payload: External Control of Assumed-Immutable Web Parameter
CVE-2026-34751 is a critical-severity external control of assumed-immutable web parameter vulnerability in payload from PayloadCMS, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected payload versions: < 3.79.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of payload you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Payloadcms | payload | < 3.79.1 | Not 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
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (github.com).
Official description
Payload is a free and open source headless content management system. Prior to version 3.79.1 in @payloadcms/graphql and payload, a vulnerability in the password recovery flow could allow an unauthenticated attacker to perform actions on behalf of a user who initiates a password reset. This issue has been patched in version 3.79.1 for @payloadcms/graphql and payload.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: External Control of Assumed-Immutable Web Parameter
The web application does not sufficiently verify inputs that are assumed to be immutable but are actually externally controllable, such as hidden form fields.
How developers prevent this class of flaw
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
More External Control of Assumed-Immutable Web Parameter vulnerabilities (CWE-472)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/payloadcms/payload/releases/tag/v3.79.1Product, Release Notes
Other vulnerabilities in payload
- 7.1 High severity
- 7.1 High severity
- 7.5 High severity
- 8.1 High severity
- 9.4 Critical severity
- 8.7 High severity
Recent External Control of Assumed-Immutable Web Parameter vulnerabilities
- 7.5 High severity
- 8.8 High severity
- 8.8 High severity
- 8.7 High severity
- 9.4 Critical severity
- 8.8 High severity
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