CVE-2025-21641

Summary

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

mptcp: sysctl: blackhole timeout: avoid using current->nsproxy

As mentioned in the previous commit, using the 'net' structure via 'current' is not recommended for different reasons:

  • Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns.

  • current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2).

The 'pernet' structure can be obtained from the table->data using container_of().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux27069e7cb3d1cea9377069266acf19b9cc5ad0ae < 4c74fbdc5ab95b13945be01e6065940b68222db7affected
LinuxLinux27069e7cb3d1cea9377069266acf19b9cc5ad0ae < 92cf7a51bdae24a32c592adcdd59a773ae149289affected
LinuxLinux6.12affected
LinuxLinux0 < 6.12unaffected
LinuxLinux6.12.10 <= 6.12.*unaffected
LinuxLinux6.13 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References