New Linux 'Copy Fail' Vulnerability Enables Root Access on Major Distributions
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2022-0847 | Local Privilege Escalation ('Dirty Pipe') in the Linux Kernel 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. | 7.8 | 90% | KEV PoC ×4 |
| mass≈1 billion+ Linux-based systems (servers, cloud VMs, Android/embedded devices) potentially vulnerable on unpatched kernels | |
| CVE-2026-31431 | Local Privilege Escalation (Copy Fail) in Linux Kernel algif_aead Interface CVE-2026-31431 ('Copy Fail') is an incorrect resource transfer between spheres (CWE-669/CWE-1288) in the Linux kernel's algif_aead implementation of the AF_ALG userspace crypto interface, introduced roughly nine years ago (around 2017, per public reporting) when commit 72548b093ee3 switched AEAD operations to in-place handling even though the source and destination buffers come from different mappings. A local, unprivileged user can trigger the flaw by performing AEAD operations through the AF_ALG socket interface, causing the kernel to mishandle the copy of ciphertext and associated data. Successful exploitation provides a reliable local privilege escalation to root (C:H/I:H/A:H per the CVSS vector). Nearly every major Linux distribution and enterprise platform is exposed, including the kernel itself, Red Hat Enterprise Linux (including AUS, EUS, TUS and Update Services for SAP Solutions), OpenShift Container Platform, Amazon Linux, Ubuntu, Debian, openSUSE Leap, SUSE CaaS Platform, NixOS, and Linux-based products from Arista and Siemens. The flaw has public proof-of-concept code, a 99.9% EPSS score, and was added to CISA's Known Exploited Vulnerabilities catalog on 2026-05-01, indicating exploitation in the wild (ransomware use is unknown). Do: Patch by installing the kernel update for CVE-2026-31431 through your distribution's security channel (Red Hat Enterprise Linux including AUS/EUS/TUS/SAP channels, OpenShift, Amazon Linux, Ubuntu, Debian, openSUSE Leap, SUSE CaaS Platform, NixOS, and Arista/Siemens firmware/software as applicable) and reboot into the patched kernel; the data provides no fixed version numbers, so defer to vendor advisories. Because the flaw is in CISA's KEV catalog (added 2026-05-01) with a 99.9% EPSS score, prioritize internet-reachable and multi-user systems first and follow BOD 22-01 guidance for cloud services. Check running kernel versions ('uname -r') and distribution advisory status to confirm you are on a fixed build. | 7.8 | 100% | KEV PoC ×5 |
| masshundreds of millions to billions of installations (servers, cloud instances, desktops, and Android/embedded devices running affected kernel generations) |
Full article497 words · extracted from thehackernews.com · click to collapse
Ravie LakshmananApr 30, 2026Linux / Vulnerability
Cybersecurity researchers have disclosed details of a Linux local privilege escalation (LPE) flaw that could allow an unprivileged local user to obtain root.
The high-severity vulnerability tracked as CVE-2026-31431 (CVSS score: 7.8) has been codenamed Copy Fail by Xint.io and Theori.
"An unprivileged local user can write four controlled bytes into the page cache of any readable file on a Linux system, and use that to gain root," the vulnerability research team at Xint.io and Theori said.
At its core, the vulnerability stems from a logic flaw in the Linux kernel's cryptographic subsystem, specifically within the algif_aead module. The issue was introduced in a source code commit made in August 2017.
Successful exploitation of the shortcoming could allow a simple 732-byte Python script to edit a setuid binary and obtain root on essentially all Linux distributions shipped since 2017, including Amazon Linux, RHEL, SUSE, and Ubuntu. The Python exploit involves four steps -
- Open an AF_ALG socket and bind to authencesn(hmac(sha256),cbc(aes))
- Construct the shellcode payload
- Trigger the write operation to the kernel's cached copy of "/usr/bin/su"
- Call execve("/usr/bin/su") to load the injected shellcode and run it as root
While the vulnerability is not remotely exploitable in isolation, a local unprivileged user can get root simply by corrupting the page cache of a setuid binary. The same primitive also has cross-container impacts as the page cache is shared across all processes on a system.
In response to the disclosure, Linux distributions have released their own advisories -
Copy Fail has its echoes in Dirty Pipe (CVE-2022-0847), another Linux kernel LPE vulnerability that could permit unprivileged users to splice data into the page cache of read-only files and ultimately overwrite sensitive files on the system to achieve code execution.
"Copy Fail is the same class of primitive, in a different subsystem," Bugcrowd's David Brumley said. "The 2017 in-place optimization in algif_aead allows a page-cache page to end up in the kernel’s writable destination scatterlist for an AEAD operation submitted over an AF_ALG socket. An unprivileged process can then drive splice() into that socket and complete a small, targeted write into the page cache of a file it doesn't own."
What makes the vulnerability dangerous is that it can be reliably triggered and does not require any race condition or kernel offset. On top of that, the same exploit works across distributions.
"This vulnerability is unique because it has four properties that almost never appear together: it's portable, tiny, stealthy, and cross-container," a Xint.io spokesperson told The Hacker News in a statement. "It allows any user account, no matter how low-level, to increase their privilege to full admin access. It also allows them to bypass sandboxing and works across all Linux versions and distributions."
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Text extracted automatically; images, tables and formatting may be missing. Original: https://thehackernews.com/2026/04/new-linux-copy-fail-vulnerability.html