CVE-2026-43500rxrpc: Also unshare DATA/RESPONSE packets when paged frags are present

Official description

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 packages & fixed versions

Affected products (as reported)

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
• https://github.com/V4bel/dirtyfrag exploit
• https://access.redhat.com/security/cve/CVE-2026-43500 vdb-entry, x_refsource_REDHAT
• RHBZ#2468273 issue-tracking, x_refsource_REDHAT
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-43500.json x_sadp-csaf-vex