CVE-2025-12887Network attack vector

Subscriber-level OAuth credential overwrite via missing authorization

Published Dec 3, 2025 · Updated Apr 8, 2026

Authorization bypass in Saad Iqbal Post SMTP 3.6.1 and earlier allows remote authenticated users to overwrite OAuth credentials. The handle_gmail_oauth_redirect function updates stored OAuth tokens without verifying that the requesting account is authorized to change them. Subscriber-level access is sufficient, and invalid or attacker-controlled credentials can alter or interrupt authenticated mail delivery.

CVSS severity5.4
Medium
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in Saad Iqbal Post SMTP 3.6.1 and earlier allows remote authenticated users to overwrite OAuth credentials. The handle_gmail_oauth_redirect function updates stored OAuth tokens without verifying that the requesting account is authorized to change them. Subscriber-level access is sufficient, and invalid or attacker-controlled credentials can alter or interrupt authenticated mail delivery.

The record

CVE
CVE-2025-12887
Published
Dec 3, 2025
Updated
Apr 8, 2026
Vendor
Fullworks Plugins
Product
Post SMTP
Classifications
CWE-862, T1098.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=3.6.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Fullworks Plugins · Post SMTPversion=0 <=3.6.1

Published CVSS scores

5.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1098.001Account Manipulation: Additional Cloud Credentials

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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