Paper/Archive/CVE-2026-74476

CVE-2026-74476

Linux Linux — veth: convert frag_list skbs before running XDP

Description · from the CVE record

In the Linux kernel, the following vulnerability has been resolved: veth: convert frag_list skbs before running XDP A frag_list skb can reach veth with data_len set but nr_frags zero. veth_convert_skb_to_xdp_buff() only converts skbs that are shared, locked, have frags[], or do not have enough headroom. It later uses skb_is_nonlinear() to decide whether to set XDP_FLAGS_HAS_FRAGS and xdp_frags_size. That exposes frag_list data to XDP as if it were stored in frags[], but frags[] is empty. AF_XDP copy mode can then trust the bogus XDP fragment metadata, walk an empty fragment entry, and crash in memcpy() from __xsk_rcv(). Route non-linear skbs through skb_pp_cow_data() before exposing them to XDP, and only advertise XDP frags when the resulting skb has frags[]. skb_copy_bits() already handles frag_list input, and skb_pp_cow_data() builds frags[] output with skb_add_rx_frag(), which is the representation XDP multi-buffer expects.

Affected

ProductAffectedFixed inSource
Linux718a18a0c8a67f97781e40bdef7cdd055c430996 – < 0be3632597b8349d43a7dc4244b492dc62a059980be3632597b8349d43a7dc4244b492dc62a05998CNA
Linux718a18a0c8a67f97781e40bdef7cdd055c430996 – < 04958dba44dc795dc79ce2fcbc117821bbbd654204958dba44dc795dc79ce2fcbc117821bbbd6542CNA
Linux718a18a0c8a67f97781e40bdef7cdd055c430996 – < 5c1c15c540fc45820ce3033c319151ec891bc10a5c1c15c540fc45820ce3033c319151ec891bc10aCNA
Linux718a18a0c8a67f97781e40bdef7cdd055c430996 – < b24ba0bbffe3e23eb2f6838881c1fabcb29fb9fbb24ba0bbffe3e23eb2f6838881c1fabcb29fb9fbCNA
Linux718a18a0c8a67f97781e40bdef7cdd055c430996 – < f9c1fff857e93be709c8b52ed1a643f37bd82c66f9c1fff857e93be709c8b52ed1a643f37bd82c66CNA
Linux718a18a0c8a67f97781e40bdef7cdd055c430996 – < d0d6415963040c401e7a7e4e482a698ba52448cbd0d6415963040c401e7a7e4e482a698ba52448cbCNA
Linux5.18–CNA

Scores by source

Linux (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: partial

References

refgit.kernel.org/stable/c/0be3632597b8349d43a7dc4244b492dc62a05998refgit.kernel.org/stable/c/04958dba44dc795dc79ce2fcbc117821bbbd6542refgit.kernel.org/stable/c/5c1c15c540fc45820ce3033c319151ec891bc10arefgit.kernel.org/stable/c/b24ba0bbffe3e23eb2f6838881c1fabcb29fb9fbrefgit.kernel.org/stable/c/f9c1fff857e93be709c8b52ed1a643f37bd82c66refgit.kernel.org/stable/c/d0d6415963040c401e7a7e4e482a698ba52448cb