CVE-2026-43500

Summary

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

rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present

The DATA-packet handler in rxrpc_input_call_event() and the RESPONSE handler in rxrpc_verify_response() copy the skb to a linear one before calling into the security ops only when skb_cloned() is true. An skb that is not cloned but still carries externally-owned paged fragments (e.g. SKBFL_SHARED_FRAG set by splice() into a UDP socket via __ip_append_data, or a chained skb_has_frag_list()) falls through to the in-place decryption path, which binds the frag pages directly into the AEAD/skcipher SGL via skb_to_sgvec().

Extend the gate to also unshare when skb_has_frag_list() or skb_has_shared_frag() is true. This catches the splice-loopback vector and other externally-shared frag sources while preserving the zero-copy fast path for skbs whose frags are kernel-private (e.g. NIC page_pool RX, GRO). The OOM/trace handling already in place is reused.

Affected Software

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

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

Additional References

• https://github.com/V4bel/dirtyfrag

kernel: “Dirty Frag” RxRPC variant is a new universal Local Privilege Escalation (LPE) vulnerability in the Linux kernel

Additional References

• https://access.redhat.com/security/cve/CVE-2026-43500
• https://bugzilla.redhat.com/show_bug.cgi?id=2468273
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43500.json

References

• https://git.kernel.org/stable/c/7c504ffab3efce8f7e4f463b314ae31030bdf18b
• https://git.kernel.org/stable/c/3711382a77342a9a1c3d2e7330dcfc7ea927f568
• https://git.kernel.org/stable/c/3eae0f4f9f7206a4801efa5e0235c25bbd5a412c
• https://git.kernel.org/stable/c/d45179f8795222ce858770dc619abe51f9d24411
• https://git.kernel.org/stable/c/aa54b1d27fe0c2b78e664a34fd0fdf7cd1960d71

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