kernelCTF: add CVE-2026-23209_cos

[4ab48b3f1ded2472]

No description provided.

[matrizzo]

Hi, it looks like your exploit doesn't build on the CI, can you fix that?

[4ab48b3f1ded2472]

The debug build issue was caused by the bug in the build system (6226291
) which is now fixed, so triggering recheck should solve that.
Not sure what is going on with vuln verify.

[matrizzo]

Hmm it looks like vuln-verify is failing because applying a patch changes the kernel's version number and kernelXDK doesn't have that kernel version in the database anymore so it throws an error.

Found 0xffffffff81000000
Using kernel base: 0xffffffff81000000
0xffff888000000000: 251
Found 0xffff888000000000
Using page_offset_base 0xffff888000000000
terminate called after throwing an instance of 'ExpKitError'
  what():  Target not found: Linux version 6.19.0-rc7+ (runner@runnervmeorf1) (gcc (Ubuntu 13.3.0-6ubuntu2~24.04.1) 13.3.0, GNU ld (GNU Binutils for Ubuntu) 2.42) #2 SMP PREEMPT_DYNAMIC Fri Apr 24 15:47:19 UTC 2026

@koczkatamas any idea how we can fix this?

[matrizzo]

So I think the problem is that the exploit is supposed to support a --vuln-trigger flag (as per the rules) which only triggers the vulnerability without initializing kernelXDK, so that it can still generate a KASAN crash even when there is no database for the KASAN kernel. I don't see this in your exploit and I think that's what causing the CI to fail.