{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-45859", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-13T15:03:33.079Z", "datePublished": "2026-05-27T12:15:39.322Z", "dateUpdated": "2026-08-05T12:28:30.933Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:28:30.933Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable nfnetlink_queue path processes packets that hit an NFQUEUE netfilter verdict; GRO-aggregated UDP traffic received from the network reaches it, so the dropping condition is triggered by remote network packets.\nAC:L - Once an nfqueue without F_GSO exists, an attacker reliably triggers the drop by sending a UDP burst that GRO coalesces into a GSO skb for a new (unconfirmed) flow; no uncontrollable condition is required.\nPR:N - Triggering the condition requires only sending network traffic to the host; no authentication or privileges are needed by the remote sender.\nUI:N - The packet drop occurs automatically during kernel packet processing with no victim interaction.\nS:U - The impact is confined to the kernel's own network packet processing; no security boundary is crossed.\nC:N - The bug only causes packets to be dropped; no kernel memory is read or disclosed.\nI:N - No data is modified or written; dropped packets are simply not delivered, which is an availability rather than integrity effect.\nA:H - All GSO-aggregated UDP packets of new (unconfirmed) conntrack flows are dropped on a non-F_GSO nfqueue, denying establishment/processing of those new flows — a sustained, network-triggerable denial of that traffic class." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/netfilter/nf_queue.h", "net/netfilter/nfnetlink_queue.c" ], "versions": [ { "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb", "lessThan": "79b713ef4261a8ead96af4703f89d0b5f25532e2", "status": "affected", "versionType": "git" }, { "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb", "lessThan": "23901aa6b8a2f294c4b774436b4691f3ff863a8f", "status": "affected", "versionType": "git" }, { "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb", "lessThan": "b740e7ddd7ca0dbfeafca3f5e52717206cf28524", "status": "affected", "versionType": "git" }, { "version": "7d8dc1c7be8d3509e8f5164dd5df64c8e34d7eeb", "lessThan": "207b3ebacb6113acaaec0d171d5307032c690004", "status": "affected", "versionType": "git" }, { "version": "6c4a0ba674f410ab99a30a16f32dac0ebfed5cd3", "status": "affected", "versionType": "git" }, { "version": "6dcc8ba8a6074bb79040f502dc66ad23a58a1c86", "status": "affected", "versionType": "git" }, { "version": "74e6eb7fd27ef1ccc68041dbc66e6d80d2e4a1a0", "status": "affected", "versionType": "git" }, { "version": "025b3326c5c409b372d0103ad30f174e55adbd1b", "status": "affected", "versionType": "git" }, { "version": "5.15.166", "lessThan": "5.16", "status": "affected", "versionType": "semver" }, { "version": "6.1.107", "lessThan": "6.2", "status": "affected", "versionType": "semver" }, { "version": "6.6.48", "lessThan": "6.7", "status": "affected", "versionType": "semver" }, { "version": "6.10.7", "lessThan": "6.11", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/netfilter/nf_queue.h", "net/netfilter/nfnetlink_queue.c" ], "versions": [ { "version": "6.11", "status": "affected" }, { "version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.75", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.14", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.4", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.12.75" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.14" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.19.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.166" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.107" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.48" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10.7" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/79b713ef4261a8ead96af4703f89d0b5f25532e2" }, { "url": "https://git.kernel.org/stable/c/23901aa6b8a2f294c4b774436b4691f3ff863a8f" }, { "url": "https://git.kernel.org/stable/c/b740e7ddd7ca0dbfeafca3f5e52717206cf28524" }, { "url": "https://git.kernel.org/stable/c/207b3ebacb6113acaaec0d171d5307032c690004" } ], "title": "netfilter: nfnetlink_queue: do shared-unconfirmed check before segmentation", "x_generator": { "engine": "bippy-1.2.0" } } } }