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

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 94.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-11 · updated 2026-08-24
Weakness: CWE-787

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 products

Linux kernel: from 5.3 (excl.) before 6.18.29; from 6.19 before 7.0.6; 5.3, 5.3-rc7, 5.3-rc8, 7.1-rc1, 7.1-rc2 — fixed in 6.18.29, 7.0.6

How to fix

Upgrade to a fixed version: Linux kernel 6.18.29, 7.0.6. Check the vendor advisory for mitigations.

References

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