CVE-2026-90049

9.3 CRITICAL

Published 2026-09-16 · Updated 2026-09-16

AI risk analysis

Summary: This flaw involves improper error handling in the Linux kernel's skb_zerocopy() function, which can lead to incorrect freeing of network buffers and potential data corruption or exposure.
Exploitability: Exploitation is moderately difficult as it requires specific conditions, such as the presence of certain network actions and the handling of fragmented packets.
Blast radius: If exploited, this vulnerability could result in data corruption, unauthorized access to network buffers, or other security issues affecting network communications.
Detection: No reliable host or network indicator is derivable from the published description.
Prioritized remediation: Upgrade to the Linux kernel version 6.1-rc1 or later, as the fix is included in this release.

networkbuffercorruption

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD description

In the Linux kernel, the following vulnerability has been resolved: net: skbuff: don't skb_tx_error() the source skb in skb_zerocopy() skb_zerocopy() copies frags from @from into @to. On an skb_orphan_frags() failure it calls skb_tx_error(@from), a destructive operation on the source skb the copy helper does not own. That completes @from's zerocopy uarg and clears SKBFL_ALL_ZEROCOPY, including the SKBFL_SHARED_FRAG page-ownership marker. Both callers already report the failure on their own drop path. nfnetlink_queue does it at nla_put_failure, and Open vSwitch does it in the flow-miss drop arm of ovs_dp_process_packet(), so nothing is lost by dropping it here. On Open vSwitch's OVS_ACTION_ATTR_USERSPACE path the skb is not freed on this error: do_execute_actions() ignores output_userspace()'s return value and, unless the upcall was the last action, keeps forwarding the same skb through the flow's remaining actions. The uarg is completed while that skb is still in flight, telling the producer its buffers are free, and SKBFL_SHARED_FRAG is cleared on an skb the rest of the stack still handles. That flag is what makes esp_input() call skb_cow_data() instead of decrypting in place, so a later local ESP delivery can decrypt over frags the skb does not own privately. Leave error reporting to the callers.

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.

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