Dirty Pipe Linux flaw allows gaining root privileges on major distros

CVE-2016-5195, widely known as 'Dirty COW', is a race condition (CWE-362) in the copy-on-write (COW) memory-handling code in mm/gup.c of the Linux kernel, affecting kernel versions 2.x through 4.x before 4.8.3. A local user with low privileges can trigger the race — including via the PTRACE_POKEDATA path used in public exploits — to write to a read-only memory mapping that should not be writable, corrupting files or overwriting memory. This yields root-level privileges on the host, enabling full system takeover, malware implantation and persistence. Any system running an affected kernel is exposed, spanning Ubuntu, Red Hat Enterprise Linux (including AUS, EUS, Long Life and TUS variants), Debian, Fedora, Palo Alto Networks PAN-OS, and NetApp Cloud Backup and HCI Storage Nodes that ship an affected kernel. Exploitation is confirmed in the wild: the flaw was actively exploited in October 2016, including by the first Android malware found using it to gain root, it was added to CISA's KEV catalog on 2022-03-03 with the required action to apply vendor updates, and EPSS currently assigns an 83.5% probability of exploitation in the next 30 days (100th percentile).

Do: Upgrade to Linux kernel 4.8.3 or later, or apply the vendor-issued patched/backported kernel updates from Canonical, Red Hat, Debian, Fedora Project, Palo Alto Networks (PAN-OS) and NetApp, per the CISA KEV required action. Prioritize unpatched legacy servers and internet-exposed Linux hosts — especially multi-user systems, SSH-accessible machines and containers where untrusted users can run code — and update Android devices that may have been silently rooted via Dirty COW. Until patching completes, restrict local and SSH access to trusted users, since exploitation requires local low-privileged code execution.

CVE-2022-0847, widely known as 'Dirty Pipe,' is a privilege escalation flaw in the Linux kernel caused by improper initialization of the 'flags' member of the new pipe buffer structure in the copy_page_to_iter_pipe and push_pipe functions, allowing stale flag values to persist (CWE-665). An unprivileged local user can trigger the flaw by writing through a pipe into the page cache of files they can read, overwriting the contents of otherwise read-only files. This enables tampering with privileged files — for example, hijacking SUID binaries per the public proof-of-concepts — to escalate privileges to root on the local system. Affected products include the Linux kernel as tracked by CISA, with downstream distribution and appliance vendors Fedora, Red Hat Enterprise Linux (including EUS, IBM Z, Power little-endian, and Real Time/NFV variants), oVirt, NetApp, Siemens, and SonicWall. Exploitation is confirmed in the wild: the flaw is on CISA's Known Exploited Vulnerabilities catalog (added 2022-04-25), carries an 89.7% EPSS probability of exploitation within 30 days, and multiple public proof-of-concept exploits are available.

Do: Apply vendor-supplied fixed kernel updates immediately per the CISA KEV required action, including patches from Fedora and Red Hat Enterprise Linux (all listed variants) and from oVirt, NetApp, Siemens, and SonicWall appliances or products that embed affected kernels; verify the running kernel version on hosts, container hosts, and appliances and reboot into the patched kernel. There is no complete workaround — the kernel itself must be patched — so prioritize multi-user servers, systems running untrusted code or containers, and internet-exposed appliances, since any local account can gain root.