CVE-2026-81000

CVE CVE-2026-81000EUVD EUVD-2026-76323Published 2026-09-11T19:42:54.000ZLast changed 2026-09-14T11:59:35.000ZCVSS 7.8

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tun_get_user() uses tun->align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is larger than the usable space in a one-page skb head, SKB_MAX_HEAD(align) underflows and the result becomes negative when stored in good_linear. That value later wraps when assigned to the size_t linear variable, and tun_alloc_skb() can place skb->data outside the allocated head. Bound the headroom stored by TUN to the one-page skb-head budget and the largest non-sentinel 16-bit skb header offset. Leave one linear byte for raw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN. Also pull the raw-TUN protocol byte and the TAP Ethernet header before accessing them, so these checks remain safe for nonlinear skbs supplied by other allocation paths.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux patch: 7.2.4; eaea34b23c46bf17b4a5638be69ab3561854f34b <379d85c7f25f3e05a428225e6b8a65613c6e9b9d; eaea34b23c46bf17b4a5638be69ab3561854f34b <708e87937de93f445225c134a2e20519f9b4ce60; patch: 6.1.188; patch: 6.6.157; patch: 5.15.221; 4.6; eaea34b23c46bf17b4a5638be69ab3561854f34b <ad715e713610d2d5473c3a6498c825ccecf26491; eaea34b23c46bf17b4a5638be69ab3561854f34b <010eee265d6bd8769b6a523d2a0693d9b3f5df43; eaea34b23c46bf17b4a5638be69ab3561854f34b <e098d9cc8859614a7f7baebc96e32a5a16b18ed2; patch: 7.3-rc1; patch: 0; patch: 6.18.50; patch: 5.10.270; eaea34b23c46bf17b4a5638be69ab3561854f34b <447c9303942c439a117d9b76ce6d6e2116b38ee7; patch: 6.12.109; eaea34b23c46bf17b4a5638be69ab3561854f34b <18ef24cdb2eba32e38f1d27f2d02b7b4212e8f76; eaea34b23c46bf17b4a5638be69ab3561854f34b <0ada54ea63e48b9c1608e917ccb7dfadbe86db28

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

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Linux — Linux

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