Embargo — ransomware group; responsible for ChipSoft Netherlands attack

UPDATE (originally noted as embargoed-and-dropped 2026-05-09): Technical details for the three CVEs cPanel patched on 2026-05-08 emerged on 2026-05-09 (The Hacker News, 2026-05-09 · NCSC-CH Security Hub post 12550, 2026-05-08 · Panelica technical analysis, 2026-05-08).

CVE-2026-29202 (CVSS 8.8) is the highest-severity item: insufficient input validation of the plugin parameter in the create_user API allows an authenticated cPanel user to inject and execute arbitrary Perl code in the context of their system account — post-authentication RCE for any cPanel user with API access. CVE-2026-29203 (CVSS 8.8) is unsafe symlink handling enabling chmod abuse on arbitrary files (privilege escalation or denial-of-service). CVE-2026-29201 (CVSS 4.3) is arbitrary feature-file disclosure. None have confirmed in-the-wild exploitation as of 2026-05-09.

The compounding risk: cPanel hosts that were compromised through the still-recent CVE-2026-41940 authentication-bypass wave (~44 000 hosting servers exploited over February–May 2026) now face a fresh post-auth Perl-execution primitive. An attacker who already used the auth bypass can pivot to CVE-2026-29202 to escalate privilege or persist. Fixed: cPanel/WHM 11.136.0.9+, 11.134.0.25+, 11.132.0.31+. Operators with auto-update disabled or version-pinned builds must run /scripts/upcp manually.

cPanel/WHM hosts that recovered from the CVE-2026-41940 wave should immediately apply the patched versions 11.136.0.9+ / 11.134.0.25+ / 11.132.0.31+ (The Hacker News, 2026-05-09 · Panelica technical analysis, 2026-05-08). CVE-2026-29202 (post-auth Perl RCE in create_user, CVSS 8.8) is the priority item; CVE-2026-29203 (CVSS 8.8 chmod abuse) and CVE-2026-29201 (CVSS 4.3 file disclosure) ship in the same update. Operators with auto-update disabled or version-pinned builds must run /scripts/upcp manually.

Researcher Hyunwoo Kim disclosed "Dirty Frag" on 2026-05-07/08 after a third party inadvertently broke embargo by reverse-engineering the upstream patch. The chain exploits two page-cache write primitives: CVE-2026-43284 (xfrm-ESP/IPsec subsystem, introduced ~2017, kernel mainline patch merged 2026-05-08) and CVE-2026-43500 (RxRPC subsystem, introduced ~2023, patch still pending at disclosure). Unlike race-condition kernel exploits, this chain is deterministic and near-100% reliable: both primitives allow userland code to write arbitrary values into read-only page-cache pages (e.g., /etc/passwd, /usr/bin/su, setuid binaries) via memory aliasing caused by DMA remapping. The combined primitive produces a stable root primitive without timing windows. Exploitation requires CAP_NET_ADMIN — available by default in Linux user namespaces on Ubuntu, Fedora, and most Arch-based distributions; restricted on RHEL 8/9 and some hardened configs. Public PoC was published alongside disclosure. Microsoft Defender telemetry confirms limited active campaigns in which threat actors escalated from SSH-compromised user accounts, modified LDAP authentication files, exfiltrated PHP session contents, and disrupted active sessions (Microsoft Security Blog, 2026-05-08 · Wiz Research, 2026-05-08 · NCSC-CH advisory 12547, 2026-05-08).

Affected distributions with confirmed exposure: Ubuntu 22.04/24.04/24.10, RHEL 8/9/10, Fedora, CentOS Stream, AlmaLinux, openSUSE Tumbleweed. Red Hat published RHSB-2026-003 (Red Hat security bulletin); Ubuntu published a fixes-available blog (Ubuntu blog). Mitigation until patches land: modprobe -r esp4 esp6 rxrpc (breaks IPsec VPNs and AFS filesystems). This is a distinct chain from CVE-2026-31431 ("Copy Fail"), also by Kim; the two vulnerabilities are not the same primitive.

Detection: Sysmon EID 1 / auditd execve on setuid binaries called from anomalous parent processes; EDR process ancestry anomalies for processes spawning as root from a non-root user context; unexpected writes to /etc/passwd or /etc/shadow detected via auditctl -w /etc/passwd -p w.