{"cve":"CVE-2026-45859","nvd":{"published":"2026-05-27T14:16:58.060","modified":"2026-10-21T13:18:57.627","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation\n\nUlrich reports a regression with nfqueue:\n\nIf an application did not set the 'F_GSO' capability flag and a gso\npacket with an unconfirmed nf_conn entry is received all packets are\nnow dropped instead of queued, because the check happens after\nskb_gso_segment().  In that case, we did have exclusive ownership\nof the skb and its associated conntrack entry.  The elevated use\ncount is due to skb_clone happening via skb_gso_segment().\n\nMove the check so that its peformed vs. the aggregated packet.\n\nThen, annotate the individual segments except the first one so we\ncan do a 2nd check at reinject time.\n\nFor the normal case, where userspace does in-order reinjects, this avoids\npacket drops: first reinjected segment continues traversal and confirms\nentry, remaining segments observe the confirmed entry.\n\nWhile at it, simplify nf_ct_drop_unconfirmed(): We only care about\nunconfirmed entries with a refcnt > 1, there is no need to special-case\ndying entries.\n\nThis only happens with UDP.  With TCP, the only unconfirmed packet will\nbe the TCP SYN, those aren't aggregated by GRO.\n\nNext patch adds a udpgro test case to cover this scenario.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-400"],"references":["https://git.kernel.org/stable/c/207b3ebacb6113acaaec0d171d5307032c690004","https://git.kernel.org/stable/c/23901aa6b8a2f294c4b774436b4691f3ff863a8f","https://git.kernel.org/stable/c/79b713ef4261a8ead96af4703f89d0b5f25532e2","https://git.kernel.org/stable/c/aead84bdacd77e08357fd718e5dcaffaf387f3c3","https://git.kernel.org/stable/c/b740e7ddd7ca0dbfeafca3f5e52717206cf28524"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-45859","score":0.00655,"percentile":0.51074,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}