CVE-2026-31431
HIGHCVE-2026-31431 is a high-severity (CVSS 7.8) CWE-669 vulnerability in Kernel. 72 public exploit references exist, so weaponization risk is real. O3 Security confirms whether CVE-2026-31431 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
crypto: algif_aead - Revert to operating out-of-place
Exploitation Status
Actively exploited in the wild
- CISA’s SSVC triage classifies this CVE as under active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-31431.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-31431 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE sits: patch-first territory.
Where this sits among everything scored
Of 0 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
KernelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.
Description
In the Linux kernel, the following vulnerability has been resolved:
crypto: algif_aead - Revert to operating out-of-place
This mostly reverts commit 72548b093ee3 except for the copying of the associated data.
There is no benefit in operating in-place in algif_aead since the source and destination come from different mappings. Get rid of all the complexity added for in-place operation and just copy the AD directly.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐧Linux | Kernel | ≥ 4.14.0&&< 5.10.254 | 5.10.254 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
theori-io/copy-fail-CVE-2026-31431
Copy Fail (CVE-2026-31431): 9-year-old Linux kernel LPE found by Theori'
tgies/copy-fail-c
Cross-platform C port of the Copy Fail Linux LPE (CVE-2026-31431). Discl
badsectorlabs/copyfail-go
A Go implementation of copyfail (CVE-2026-31431)
Percivalll/Copy-Fail-CVE-2026-31431-Kubernetes-PoC
PoC: fully unprivileged container escape to node-level code execution on
Sndav/CVE-2026-31431-Advanced-Exploit
CVE-2026-31431 纯文件利用
painoob/Copy-Fail-Exploit-CVE-2026-31431
Most Linux LPEs need a race window or a kernel-specific offset. Copy Fai
sgkdev/page_inject
CVE-2026-31431-killed page-cache exploit — code exec into containers sha
Crihexe/copy-fail-tiny-elf-CVE-2026-31431
Minimal no-libc Linux x86_64 ELF PoC build for Copy Fail (CVE-2026-31431
shadowabi/CVE-2026-31431-CopyFail-Universal-LPE
CVE-2026-31431 Copy Fail — Universal LPE exploit. Dynamic ELF offset + f
iss4cf0ng/CVE-2026-31431-Linux-Copy-Fail
Rust implementation Exploit/PoC of CVE-2026-31431-Linux-Copy-Fail, allow
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Kernel to 5.10.254 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-31431 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-31431 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-31431. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This issue is classified as Important, rather than Critical severity, because exploitation requires local access to the system. A low-privileged local attacker can exploit this flaw in the Linux kernel's cryptographic interface to gain root privileges by overwriting sensitive system files. Exploitation does not…
Frequently Asked Questions
Is CVE-2026-31431 in your dependencies?
O3 detects CVE-2026-31431 across Linux dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.