Administrative access via CRLF session-file injection
Published Apr 29, 2026 · Updated Apr 29, 2026
Authentication bypass in WebPros cPanel, WHM, and WP Squared allows remote attackers to obtain unauthenticated administrative access. The cpsrvd daemon accepts raw CRLF characters from Basic authentication data and writes injected properties, including a privileged user value, into a pre-authentication session file. Reloading that file promotes the attacker's session token to administrative access, exposing the managed host, configuration, databases, and websites.
Summary
What happened
Authentication bypass in WebPros cPanel, WHM, and WP Squared allows remote attackers to obtain unauthenticated administrative access. The cpsrvd daemon accepts raw CRLF characters from Basic authentication data and writes injected properties, including a privileged user value, into a pre-authentication session file. Reloading that file promotes the attacker's session token to administrative access, exposing the managed host, configuration, databases, and websites.
The record
- CVE
- CVE-2026-41940
- Published
- Apr 29, 2026
- Updated
- Apr 29, 2026
- Vendor
- cPanel, L.L.C.
- Product
- WHM
- Classifications
- CWE-306, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 29, 2026CVE publishedPublication date reported by the CVE source.
- Apr 29, 2026Record updatedLatest update available in the CVE record.
- Apr 30, 2026Exploitation reportedCISA Known Exploited Vulnerabilities catalog entry
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=11.110.0 <11.110.0.97
- Affected versionversion=11.118.0 <11.118.0.63
- Affected versionversion=11.126.0 <11.126.0.54
- Affected versionversion=11.132.0 <11.132.0.29
- Affected versionversion=11.134.0 <11.134.0.20
- Affected versionversion=11.136.0 <11.136.0.5
What conditions does exploitation require?
What is affected?
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.
View daily counts
| Reporting day | Unique IPs |
|---|---|
| Sep 22, 2026 | 79 |
| Sep 23, 2026 | 67 |
| Sep 24, 2026 | 74 |
| Sep 25, 2026 | 66 |
| Sep 26, 2026 | 85 |
| Sep 27, 2026 | 78 |
| Sep 28, 2026 | 81 |
Weakness, pattern, technique
Public exploit references
- watchTowr cPanel/WHM Authentication Bypass Detection Artifact Generatorfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Broad in-the-wild exploitationreported exploitation
- CISA Known Exploited Vulnerabilities catalog entryknown exploited catalog
- Mirai botnet exploitationbotnet
- Sorry ransomware exploitationransomware
- Shadowserver honeypot exploit attemptshoneypot
Technologies
Your stack
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Your stack
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