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Security researcher Hyunwoo Kim (v4bel) publicly disclosed a new Linux kernel local privilege escalation class, dubbed “Dirty Frag,” after an embargo was broken on May 7–8, 2026.
Dirty Frag chains two page-cache write flaws — xfrm‑ESP Page‑Cache Write and RxRPC Page‑Cache Write — to allow an unprivileged local user to obtain root on major distributions (Ubuntu, RHEL/CentOS/AlmaLinux, Fedora, openSUSE and others). The weakness sits in decryption fast paths (esp4, esp6, rxrpc kernel modules) and is deterministic with a high success rate; proof‑of‑concept code and a technical writeup were posted to GitHub.
No upstream patch or CVE had landed at disclosure, though AlmaLinux published early test fixes and maintainers are working on backports.
Immediate mitigations include blacklisting/removing the esp4, esp6 and rxrpc modules via modprobe configuration (example command published in advisories). The flaw is related to earlier “Dirty Pipe” and “Copy Fail” bugs and can bypass some prior mitigations, raising urgent concerns for administrators of multiuser and cloud systems.
🔗 Based On
🕰️ The Story So Far: An Evolving Timeline
Friday, May 8, 2026 02:57 UTC
Dirty Frag Linux Local Privilege Bug Exposed
Monday, May 4, 2026 22:57 UTC
Critical 'Copy Fail' Linux kernel vulnerability prompts urgent patching






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