CVE-2025-71304

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

smack: /smack/doi: accept previously used values

Writing to /smack/doi a value that has ever been

written there in the past disables networking for

non-ambient labels.

E.g.

# cat /smack/doi

3

# netlabelctl -p cipso list

Configured CIPSO mappings (1)

DOI value : 3

mapping type : PASS_THROUGH

# netlabelctl -p map list

Configured NetLabel domain mappings (3)

domain: "_" (IPv4)

protocol: UNLABELED

domain: DEFAULT (IPv4)

protocol: CIPSO, DOI = 3

domain: DEFAULT (IPv6)

protocol: UNLABELED

# cat /smack/ambient

_

# cat /proc/$$/attr/smack/current

_

# ping -c1 10.1.95.12

64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.964 ms

# echo foo >/proc/$$/attr/smack/current

# ping -c1 10.1.95.12

64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.956 ms

unknown option 86

# echo 4 >/smack/doi

# echo 3 >/smack/doi

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References