How severe is CVE-2026-105863?

No CVSS score has been assigned to CVE-2026-105863 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-105863?

CVE-2026-105863 affects the following packages: payload (npm), payload (npm). Ecosystems affected: npm.

How do I fix CVE-2026-105863?

Update payload to 3.90.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-105863 is resolved across your whole dependency graph.

How do I detect CVE-2026-105863 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for payload, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-105863 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-105863 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-105863 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-105863?

CVE-2026-105863 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 30th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-105863?

CVE-2026-105863 is classified as CWE-290 (CWE-290), CWE-915 (CWE-915). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-105863 published, and has it been updated?

CVE-2026-105863 was published on October 6, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-105863 — payload

Fix: payloadcms/payload@56cd5cd

CVE-2026-105863 is a CWE-290 vulnerability in payload. A fix is available for payload — see the affected versions and patch details below.

Payload authentication token field handling issue

Also known asGHSA-66wr-7vmr-p5jq

Published

Oct 6, 2026

Updated

Oct 21, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-105863.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs30th percentile — riskier than 30% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

115other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

payloadnpm

629Kdownloads / week

Description

Impact

Under certain field configurations, Payload could include unintended values in the authentication token issued at login.

You are affected if:

You use an affected Payload version and have configured a custom field option that maps a field to a reserved authentication claim name.

Patches

Payload now restricts which field configuration options can influence the contents of the authentication token.

Users should upgrade payload packages to >= 3.90.0 or >= 4.0.0-canary.34.

Workarounds

There is no complete workaround. Users should upgrade payload packages to >= 3.90.0 or >= 4.0.0-canary.34.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`payload`	≥ 3.0.0&&< 3.90.0	3.90.0`npm install payload@3.90.0`
📦npm	`payload`	≥ 4.0.0-canary.0&&< 4.0.0-canary.34	4.0.0-canary.34`npm install payload@4.0.0-canary.34`

Affected Products

1 product · 35 configurations

Application

payloadpayloadcms

≥ 3.0.0 && < 3.90.0

1 version

4.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for payload, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update payload to 3.90.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-105863 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact Under certain field configurations, Payload could include unintended values in the authentication token issued at login. You are affected if: - You use an affected Payload version and have configured a custom field option that maps a field to a reserved authentication claim name. ### Patches Payload now restricts which field configuration options can influence the contents of the authentication token. Users should upgrade payload packages to `>= 3.90.0` or `>= 4.0.0-canary.34`. ### Workarounds There is no complete workaround. Users should upgrade payload packages to `>= 3.90.0

O3 Security · Impact-Aware SCA

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