Two new page-cache-write LPE modules, both ported from the public V12
security PoCs (github.com/v12-security/pocs):
- dirtydecrypt (CVE-2026-31635): rxgk missing-COW in-place decrypt.
rxgk_decrypt_skb() decrypts spliced page-cache pages before the HMAC
check, corrupting the page cache of a read-only file. Sibling of
Copy Fail / Dirty Frag in the rxrpc subsystem.
- fragnesia (CVE-2026-46300): XFRM ESP-in-TCP skb_try_coalesce() loses
the SHARED_FRAG marker, so the ESP-in-TCP receive path decrypts
page-cache pages in place. A latent bug exposed by the Dirty Frag
fix (f4c50a4034e6). Retires the old _stubs/fragnesia_TBD stub.
Both wrap the PoC exploit primitive in the skeletonkey_module
interface: detect/exploit/cleanup, an --active /tmp sentinel probe,
--no-shell support, and embedded auditd + sigma rules. The exploit
body runs in a forked child so the PoC's exit()/die() paths cannot
tear down the dispatcher. The fragnesia port drops the upstream PoC's
ANSI TUI (incompatible with a shared dispatcher); the exploit
mechanism is reproduced faithfully. Linux-only code is guarded with
#ifdef __linux__ so the modules still compile on non-Linux dev boxes.
VERIFICATION: ported, NOT yet validated end-to-end on a
vulnerable-kernel VM. The CVE fix commits are not pinned, so detect()
is precondition-only (PRECOND_FAIL / TEST_ERROR, never a blind
VULNERABLE) and --auto will not fire them unless --active confirms.
macOS stub-path compiles verified locally; the Linux exploit-path
build is covered by CI (build.yml, ubuntu) only. See each MODULE.md.
Wiring: core/registry.h, skeletonkey.c, Makefile, CVES.md, ROADMAP.md.
