● High · CVSS 7.1

How to Fix CVE-2026-4100: CWE-862 Missing Authorization

Q: Is CVE-2026-4100 being exploited in the wild?

As of 2026-05-25, CVE-2026-4100 is not listed in the CISA Known Exploited Vulnerabilities catalog. Watch the catalog and patch on a normal cadence; KEV status can change as exploitation evidence emerges.

Q: What is the CVSS score for CVE-2026-4100?

The CVSS base score is 7.1 (High).

Q: What version fixes this?

The vendor advisory names the patched build. See the References section.

Q: Will a WAF or IDS rule alone close this?

No. Network filters cut down opportunistic scans but they do not remove the flaw. The vendor patch is the only durable fix.

By Sai Kiran Pandrala

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Last verified: 2026-05-25

CVE-2026-4100 is a cwe-862 missing authorization in strangerstudios Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions. Fix it by upgrading to the patched build from the vendor advisory.

⚡ At a glance


Severity	CVSS 7.1 - High
Actively exploited?	Not currently in the CISA KEV catalog
Affected	Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions 0 up to (including) 3.6.5
Fixed in	See vendor advisory
Type (CWE)	CWE-862: CWE-862 Missing Authorization

What is CVE-2026-4100?

CVE-2026-4100 is a cwe-862 missing authorization flaw in strangerstudios Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions. It carries a CVSS base score of 7.1 (high). It is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

From the source record: The Paid Memberships Pro plugin for WordPress is vulnerable to unauthorized modification and disruption of Stripe webhook configuration in all versions up to, and including, 3.6.5. This is due to missing capability checks on the wp_ajax_pmpro_stripe_create_webhook, wp_ajax_pmpro_stripe_delete_webhook, and wp_ajax_pmpro_stripe_rebuild_webhook AJAX handlers. This makes it possible for authenticated attackers, with Subscriber-level access and above, to delete, create, or rebuild the site's Stripe webhook, disrupting all payment processing, subscription renewal synchronization, cancellation handling, and failed payment management.

Why it matters in practice: The blast radius depends on how the affected service is exposed. An internet-facing instance with no compensating controls is the highest-risk configuration.

Am I affected?

You are affected if your installation of Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions matches a version listed in the Affected row above.

Check the running version against the Affected row above using the product's admin console or --version flag.

How to fix CVE-2026-4100

Apply the vendor patch. Target the build named in the Fixed in row above (See vendor advisory). The runnable command set below covers the most common deployment patterns for Paid Memberships Pro – Content Restriction, User Registration, & Paid Subscriptions.

macOS update


softwareupdate --list
sudo softwareupdate -i -a -R
sw_vers -productVersion

After applying the patch

Restart the service or device so the patched binary loads.
Confirm the running version matches the Fixed in row using the verification command below.
Rotate credentials and API keys that the affected service could access if the asset was exposed during the disclosure window.

If you can't patch immediately

Until the patch lands, narrow the attack surface with these runnable controls.

Restrict network exposure

Block public access to the affected service at the perimeter. Allow only trusted source IPs.


# Linux iptables: only allow trusted admin subnet
sudo iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 443 -j DROP
sudo iptables-save | sudo tee /etc/iptables/rules.v4


# Windows firewall: only allow trusted admin subnet on management port
New-NetFirewallRule -DisplayName "Restrict-Mgmt-Allow" -Direction Inbound -Action Allow `
  -RemoteAddress 10.10.10.0/24 -Protocol TCP -LocalPort 443
New-NetFirewallRule -DisplayName "Restrict-Mgmt-Deny"  -Direction Inbound -Action Block `
  -Protocol TCP -LocalPort 443

Mitigations are temporary. Apply the vendor patch as soon as a maintenance window opens.

How to verify the fix worked

Confirm the patched build is the one actually running.

Check the running version against the Affected row above using the product's admin console or --version flag.

Expected: a version at or above the patched build named in the vendor advisory.

Also worth doing: pull recent log windows for indicators of compromise listed in the vendor advisory, and re-run an authenticated vulnerability scan with up-to-date signatures.

Frequently asked questions

Is CVE-2026-4100 being exploited in the wild?