Fragnesia is a new Linux LPE vulnerability in ESP/XFRM/skbuff.c code, allowing arbitrary byte writes into the kernel page cache of read-only files; PoC is already public.
Key Takeaways
Fragnesia follows Dirty Frag, disclosed last week, and shares the same vulnerability class: local privilege escalation via kernel page cache manipulation.
The bug is a logic error in ESP/XFRM code enabling arbitrary byte writes into read-only file kernel page cache.
A two-line patch targeting skbuff.c exists but has not yet been mainlined or picked up by any kernel release.
Proof of concept code is already publicly available, raising immediate risk for unpatched systems.
Disclosed by V12 Security on the oss-security mailing list; full details available there.
