Failed to reproduce on my Debian VM.

[aravinda333]

Hi, I tried reproducing this CVE on my Debian system and it failed with rc=4.

Is my system immune from this vulnerability ?

Linux debian 6.1.0-43-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.162-1 (2026-02-08) x86_64 GNU/Linux

[Hontiris1]

Short answer: Your system is NOT automatically immune. Here's the accurate picture.

rc=4 is the PoC's exit code, but its exact meaning (precondition fail vs. environment mismatch) is
not formally documented in the PoC source. It does indicate the exploit did not fully execute, but
this does not confirm your kernel is patched.

Your kernel 6.1.162-1 (build date: 2026-02-08) predates the DirtyFrag public disclosure
(2026-05-07) and the upstream patches (CVE-2026-43284 patched 2026-05-08). This means that build
cannot contain the DirtyFrag-specific fix. Debian's security tracker confirms both CVEs affect Debian:

• CVE-2026-43284 (esp_input, xfrm-ESP): https://security-tracker.debian.org/tracker/CVE-2026-43284
• CVE-2026-43500 (RxRPC): https://security-tracker.debian.org/tracker/CVE-2026-43500

Check if you have a newer kernel update available or applied:

apt-get update && apt-cache policy linux-image-$(uname -r)
uname -r  # confirm currently running kernel

Check if vulnerable modules are present/loaded (absence of esp4/esp6/rxrpc = not immediately
exploitable, but esp4/esp6 autoload on demand):

lsmod | grep -E "esp4|esp6|rxrpc"
modinfo esp4 esp6 rxrpc 2>/dev/null | grep filename

Immediate mitigation if unpatched:

sudo sh -c "printf 'install esp4 /bin/false\ninstall esp6 /bin/false\ninstall rxrpc /bin/false\n' \
> /etc/modprobe.d/dirtyfrag.conf; rmmod esp4 esp6 rxrpc 2>/dev/null; true"

Monitor: https://security-tracker.debian.org/tracker/CVE-2026-43284