QiAnXin XLab has tied the ongoing exploitation of cPanel's CVE-2026-41940 to a previously-quiet threat actor it tracks as Mr_Rot13, who has been operating since at least 2020. The attack chain exploits the cPanel and WHM authentication bypass to drop a Go-based infector that adds an attacker SSH key, plants a PHP web shell, and serves a fake login page to steal cPanel credentials (ROT13-encoded, exfiltrated to wrned[.]com). The final payload is a cross-platform backdoor called Filemanager that runs on Windows, macOS, and Linux. XLab counts over 2,000 attacker source IPs currently scanning for this flaw.
cPanel released patches Friday for three new vulnerabilities. The two worst (CVE-2026-29202 and CVE-2026-29203, both CVSS 8.8) let authenticated users execute arbitrary Perl code through the create_user API or escalate privileges via unsafe symlink chmod. The third (CVE-2026-29201, CVSS 4.3) lets authenticated users read arbitrary files. No exploitation observed yet. The disclosure lands while attackers are still mass-exploiting CVE-2026-41940 to deploy 'Sorry' ransomware against cPanel hosts, including a wave targeting government agencies and MSPs (covered May 5). Hosting providers face a compounding patch burden.
Update on the cPanel ransomware wave covered May 3: attackers have shifted focus and are now targeting governments and managed service providers exploiting CVE-2026-41940. Security Affairs reports the operation is no longer just opportunistic mass-encryption of small business websites - the actors are deliberately looking for hosting accounts owned by government agencies and IT firms that manage downstream customers. CISA added the cPanel flaw to its KEV catalog Friday with a federal patch deadline of May 21. With 44,000 cPanel hosts already compromised in the initial wave, the secondary phase targeting MSPs has the potential to multiply impact through customer-tenant relationships - much like the 2023 Kaseya VSA campaign.
Update on the cPanel flaw covered April 30: attackers are now mass-exploiting CVE-2026-41940 to deploy a Linux ransomware called 'Sorry' that encrypts websites and demands payment to unlock them. Shadowserver confirms at least 44,000 cPanel hosts have been compromised, with hundreds of victim sites already showing up in Google search results. The Sorry encryptor is written in Go, uses ChaCha20 with an embedded RSA-2048 public key (so victims cannot recover files without the attacker's private key), and appends '.sorry' to filenames. KnownHost reports the cPanel flaw was being exploited as a zero-day since at least February 23.
cPanel disclosed a critical authentication bypass on Monday affecting every cPanel and WHM version - including end-of-life builds. CVSS 9.8. The bug let unauthenticated attackers log in as administrators by abusing how the cPanel session daemon writes session files during login. Hosting providers including Namecheap, KnownHost, hosting.com, HostPapa, and InMotion took cPanel and WHM offline globally for hours while patches deployed. Researchers at watchTowr published a working proof-of-concept on April 29. KnownHost reports possible targeted exploitation as early as February 23, 2026 - more than two months before disclosure.
TrustStrike Labs