CVE-2026-91831Network attack vector

Sender spoofing via unsanitized notification sender-name setting

Published Oct 19, 2026 · Updated Oct 19, 2026

Email header injection in Subscribe to Comments before 2.3.3 allows remote authenticated users to spoof senders via plugin settings. The notification sender-name setting accepts newline characters that become additional email headers, including a hidden Bcc. Author-level access or above is required, and the impact concerns outgoing notification messages rather than arbitrary code execution.

CVSS severity3.8
Low
EPSS probability0.16%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Email header injection in Subscribe to Comments before 2.3.3 allows remote authenticated users to spoof senders via plugin settings. The notification sender-name setting accepts newline characters that become additional email headers, including a hidden Bcc. Author-level access or above is required, and the impact concerns outgoing notification messages rather than arbitrary code execution.

The record

CVE
CVE-2026-91831
Published
Oct 19, 2026
Updated
Oct 19, 2026
Vendor
Mark Jaquith
Product
Subscribe to Comments
Classifications
CWE-93
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 19, 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=2.3 <2.3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mark Jaquith · Subscribe to Commentsversion=2.3 <2.3.3

Published CVSS scores

3.8WPScanCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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