{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-37823", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:23.947Z", "datePublished": "2025-05-08T06:26:16.839Z", "dateUpdated": "2026-08-05T11:57:46.765Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:57:46.765Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: hfsc: Fix a potential UAF in hfsc_dequeue() too\n\nSimilarly to the previous patch, we need to safe guard hfsc_dequeue()\ntoo. But for this one, we don't have a reliable reproducer." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation requires configuring an HFSC qdisc hierarchy with a netem/codel child and deleting a class via rtnetlink (RTM_NEWQDISC/RTM_NEWTCLASS/RTM_DELTCLASS), which is a local netlink socket operation. Per kernel scoring guidance, tc/netlink qdisc bugs are Local.\nAC:L - The attacker deterministically controls every element: the HFSC class curves (HFSC_RSC), the child qdisc's drop-on-dequeue behavior (netem loss/corrupt/nested-child enqueue failure, or aggressive codel parameters), packet injection, and the moment of class deletion; the whole sequence runs serialized under the qdisc/tree lock with no race to win. The absence of a maintainer reproducer reflects effort not spent, not a condition outside attacker control — the identical primitive in the companion commit 3df275ef0a6a had a reliable reproducer.\nPR:L - The rtnetlink handlers gate on netlink_net_capable(skb, CAP_NET_ADMIN), which is evaluated against the caller's netns user_ns, so an unprivileged user obtains it simply with `unshare -Urn` and can then create a dummy/veth device plus the full hfsc+netem hierarchy. No real root in the init namespace is needed.\nUI:N - The attacker performs the entire sequence — qdisc/class setup, packet transmission, and class deletion — from their own process. No victim action is involved.\nS:U - The corruption stays within the kernel's own memory and privilege domain, yielding standard local privilege escalation rather than crossing into another security authority such as a hypervisor or IOMMU boundary.\nC:H - The freed struct hfsc_class remains linked in the scheduler's eligible rbtree and is subsequently dereferenced, so a heap spray of the kmalloc-1k slot lets the attacker read back kernel data through the reclaimed object and its cl->qdisc pointer chain, giving effectively arbitrary kernel memory disclosure.\nI:H - After the free, hfsc_dequeue() performs an indirect call via qdisc_dequeue_peeked() through sch->dequeue read from the reclaimed object, plus bstats_update() writes and rb_erase()/rb_insert_color() on attacker-controlled node pointers — a direct control-flow hijack and arbitrary-write primitive leading to full kernel compromise.\nA:H - Even without successful heap grooming, traversing and erasing a freed rbtree node and calling through a stale function pointer reliably produces a kernel oops/panic, and the attacker can trigger it repeatedly for a complete denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_hfsc.c" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "68f256305ceb426d545a0dc31f83c2ab1d211a1e", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "2f46d14919c39528c6e540ebc43f90055993eedc", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "da7936518996d290e2fcfcaf6cd7e15bfd87804a", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "11bccb054c1462fb069219f8e98e97a5a730758e", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "76c4c22c2437d3d3880efc0f62eca06ef078d290", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "c6f035044104c6ff656f4565cd22938dc892528c", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "c6936266f8bf98a53f28ef9a820e6a501e946d09", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "6ccbda44e2cc3d26fd22af54c650d6d5d801addf", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_hfsc.c" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.293", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.237", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.181", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.136", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.89", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.26", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14.5", "lessThanOrEqual": "6.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15", "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": "2.6.12", "versionEndExcluding": "5.4.293" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.10.237" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.15.181" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.136" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.89" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.26" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.14.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.15" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/68f256305ceb426d545a0dc31f83c2ab1d211a1e" }, { "url": "https://git.kernel.org/stable/c/2f46d14919c39528c6e540ebc43f90055993eedc" }, { "url": "https://git.kernel.org/stable/c/da7936518996d290e2fcfcaf6cd7e15bfd87804a" }, { "url": "https://git.kernel.org/stable/c/11bccb054c1462fb069219f8e98e97a5a730758e" }, { "url": "https://git.kernel.org/stable/c/76c4c22c2437d3d3880efc0f62eca06ef078d290" }, { "url": "https://git.kernel.org/stable/c/c6f035044104c6ff656f4565cd22938dc892528c" }, { "url": "https://git.kernel.org/stable/c/c6936266f8bf98a53f28ef9a820e6a501e946d09" }, { "url": "https://git.kernel.org/stable/c/6ccbda44e2cc3d26fd22af54c650d6d5d801addf" } ], "title": "net_sched: hfsc: Fix a potential UAF in hfsc_dequeue() too", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:55:56.301Z" } } ] } }