CVE-2026-89487

CVE CVE-2026-89487EUVD EUVD-2026-76393Published 2026-09-11T19:43:40.000ZLast changed 2026-09-14T12:00:22.000ZCVSS 7.8

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: openvswitch: only skb_tx_error() a packet we are about to drop queue_userspace_packet() borrows the packet skb -- it only copies it into a private netlink message (user_skb) and does not own it; on return do_execute_actions() keeps forwarding it through the flow's remaining actions. Its error path nevertheless calls skb_tx_error(skb), which via skb_zcopy_clear() does skb_shinfo(skb)->flags &= ~SKBFL_ALL_ZEROCOPY, stripping SKBFL_SHARED_FRAG from that live skb (skb_tx_error()'s kerneldoc says "skb must be freed afterwards"). For a MSG_ZEROCOPY skb carrying page-cache frags, SKBFL_SHARED_FRAG is what makes esp_input() skb_cow_data() before in-place AEAD; once it is stripped a later local ESP-in-UDP delivery decrypts in place over pages the sender does not own -- an unprivileged page-cache write (the "Fragnesia" primitive). do_execute_actions() ignores output_userspace()'s return value, so any action after a failed USERSPACE upcall inherits the stripped skb. Move the skb_tx_error() to the flow-miss drop path - the "default" branch of ovs_dp_process_packet()'s switch(error), before kfree_skb(). The call has been here since commit 36d5fe6a0007 ("core, nfqueue, openvswitch: Orphan frags in skb_zerocopy and handle errors") but was harmless until esp_input() began relying on SKBFL_SHARED_FRAG to gate in-place decrypt; only then did stripping it on a still-forwarded skb become a page-cache write primitive.

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 36d5fe6a000790f56039afe26834265db0a3ad4c <48db11e115d1b232edc5591604adc6eda95cd545; patch: 6.1.188; patch: 6.18.50; 36d5fe6a000790f56039afe26834265db0a3ad4c <4d5c460ef8754be1d43b16dbf02695b008b207d6; patch: 7.3-rc1; 36d5fe6a000790f56039afe26834265db0a3ad4c <e41a59fc056f63a7a1f42788913c53cc48d744aa; patch: 6.12.109; 36d5fe6a000790f56039afe26834265db0a3ad4c <0dbc2398fca3bb33eda963849f865ddb1b3aa05e; patch: 0; patch: 5.10.270; patch: 6.6.157; 36d5fe6a000790f56039afe26834265db0a3ad4c <6767d70cf46f65807a6a4c4406a518e6c12e36ae; patch: 5.15.221; 36d5fe6a000790f56039afe26834265db0a3ad4c <5d85eef222cfd28e73deed7402c100229e8b9e6e; 3.14; 36d5fe6a000790f56039afe26834265db0a3ad4c <4477222e2916a18e273edc139c955ade6bbb7a69; c5f0c0e7525443add533495e93ba8de6feab2396; patch: 7.2.4; 3.12.40 <3.13; 36d5fe6a000790f56039afe26834265db0a3ad4c <5de5d554141a15b3f1f5c978fd9f7f4fd6d0600a; 1674b4bf3eea3cac51b70778e89f8025f7cfe695; 3.10.51 <3.11

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

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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