{ "schemaVersion": 1, "attribution": [ { "source": "CISA Known Exploited Vulnerabilities", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog", "licence": "US government work" }, { "source": "GitHub Advisory Database", "url": "https://github.com/advisories", "licence": "CC BY 4.0" }, { "source": "Have I Been Pwned", "url": "https://haveibeenpwned.com/", "licence": "CC BY 4.0" }, { "source": "CVE Program (CVE records)", "url": "https://www.cve.org/Legal/TermsOfUse", "licence": "CVE Terms of Use", "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.", "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy." }, { "source": "FIRST EPSS", "url": "https://www.first.org/epss/", "licence": "free to use; FIRST requests attribution" } ], "record": { "id": "CVE-2026-74284", "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-74284", "idYear": 2026, "status": "PUBLISHED", "publishedAt": "2026-08-15T05:57:53.290Z", "updatedAt": "2026-08-17T05:16:29.785Z", "importedAt": "2026-10-24T01:58:30.346Z", "snapshot": { "id": "cve_2026-10-24_midnight_baseline", "at": "2026-10-24T00:00:00.000Z", "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z" }, "facts": { "title": "net/sched: sch_hfsc: Don't make class passive twice", "summary": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_hfsc: Don't make class passive twice\n\nupdate_vf() is called from two places for the same class during a single\ndequeue when the class's child qdisc (e.g. codel/fq_codel) drops its last\npackets while dequeuing:\n\n1. The child calls qdisc_tree_reduce_backlog(), which, now that the child\n is empty, invokes hfsc_qlen_notify() -> update_vf(cl, 0, 0) and turns\n the class passive (cl_nactive is decremented up the hierarchy).\n\n2. hfsc_dequeue() then calls update_vf(cl, qdisc_pkt_len(skb), cur_time)\n to charge the dequeued bytes.\n\nOn the second call the class is already passive, but its child qdisc is\nstill empty, so update_vf() arms go_passive again:\n\n if (cl->qdisc->q.qlen == 0 && cl->cl_flags & HFSC_FSC)\n go_passive = 1;\n\nThe leaf is then skipped by the cl_nactive == 0 check inside the loop,\nwhich does not clear go_passive, so the stale go_passive propagates to the\nparent and decrements its cl_nactive a second time. A parent that still\nhas other active children is driven to cl_nactive == 0 and removed from\nthe vttree, even though those siblings are still backlogged. They are\nnever dequeued again and the qdisc stalls.\n\nFix this by only arming go_passive when the class is actually active, so an\nalready-passive class no longer triggers a second passive transition. The\nbyte accounting (cl->cl_total += len) still runs for every ancestor, so\ndequeued bytes continue to be counted exactly once.", "affected": [ { "vendor": "Linux", "product": "Linux", "defaultStatus": "unaffected", "versions": [ { "version": "72c61ffbeeb8c50f6d4d70c65d3283aa1bac57a7", "status": "affected", "versionType": "git", "lessThan": "a425c82ff06cda5165e0de3de8c2a445ec1f863e" }, { "version": "a5efc95a33bd4fcb879250852828cc58c7862970", "status": "affected", "versionType": "git", "lessThan": "fc973ecd1a079b9a87c360478542f3a56dea085b" }, { "version": "0475c85426b18eccdcb7f9fb58d8f8e9c6c58c87", "status": "affected", "versionType": "git", "lessThan": "15720cd8fa3fc625146128f89a8e11b0449a20a7" }, { "version": "9030a91235ae4845ec71902c3e0cecfc9ed1f2df", "status": "affected", "versionType": "git", "lessThan": "b2a017bfcf565721918ec7355a373911d2f2a227" }, { "version": "d06476714d2819b550e0cc39222347e2c8941c9d", "status": "affected", "versionType": "git", "lessThan": "9221a594c72a1446137926d4c2aa04e345f798dc" }, { "version": "51eb3b65544c9efd6a1026889ee5fb5aa62da3bb", "status": "affected", "versionType": "git", "lessThan": "66dbb13eeb2fc339f8f548a9076be4c1a94857b0" }, { "version": "51eb3b65544c9efd6a1026889ee5fb5aa62da3bb", "status": "affected", "versionType": "git", "lessThan": "3a49bbae676fef1ffe548971e6229ae2adeb9d10" }, { "version": "51eb3b65544c9efd6a1026889ee5fb5aa62da3bb", "status": "affected", "versionType": "git", "lessThan": "90b662ea25f5e83bb3b8ccec5b93ced810b92fb8" }, { "version": "9a5fd5c2f4d4afdd5e405083ee53e0789ce76956", "status": "affected", "versionType": "git" }, { "version": "c1175c4ad01dbc9c979d099861fa90a754f72059", "status": "affected", "versionType": "git" }, { "version": "5.10.241", "status": "affected", "versionType": "semver", "lessThan": "5.10.261" }, { "version": "5.15.190", "status": "affected", "versionType": "semver", "lessThan": "5.15.212" }, { "version": "6.1.138", "status": "affected", "versionType": "semver", "lessThan": "6.1.178" }, { "version": "6.6.90", "status": "affected", "versionType": "semver", "lessThan": "6.6.145" }, { "version": "6.12.28", "status": "affected", "versionType": "semver", "lessThan": "6.12.97" }, { "version": "5.4.297", "status": "affected", "versionType": "semver", "lessThan": "5.5" }, { "version": "6.14.6", "status": "affected", "versionType": "semver", "lessThan": "6.15" } ] }, { "vendor": "Linux", "product": "Linux", "defaultStatus": "affected", "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "status": "unaffected", "versionType": "semver", "lessThan": "6.15" }, { "version": "5.10.261", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.10.*" }, { "version": "5.15.212", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "5.15.*" }, { "version": "6.1.178", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.1.*" }, { "version": "6.6.145", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.6.*" }, { "version": "6.12.97", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.12.*" }, { "version": "6.18.40", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "6.18.*" }, { "version": "7.1.5", "status": "unaffected", "versionType": "semver", "lessThanOrEqual": "7.1.*" }, { "version": "7.2", "status": "unaffected", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*" } ] } ] } } }