{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38115", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:23.986Z", "datePublished": "2025-07-03T08:35:23.750Z", "dateUpdated": "2026-08-05T11:59:39.505Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:59:39.505Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: sch_sfq: fix a potential crash on gso_skb handling\n\nSFQ has an assumption of always being able to queue at least one packet.\n\nHowever, after the blamed commit, sch->q.len can be inflated by packets\nin sch->gso_skb, and an enqueue() on an empty SFQ qdisc can be followed\nby an immediate drop.\n\nFix sfq_drop() to properly clear q->tail in this situation.\n\n\nip netns add lb\nip link add dev to-lb type veth peer name in-lb netns lb\nethtool -K to-lb tso off # force qdisc to requeue gso_skb\nip netns exec lb ethtool -K in-lb gro on # enable NAPI\nip link set dev to-lb up\nip -netns lb link set dev in-lb up\nip addr add dev to-lb 192.168.20.1/24\nip -netns lb addr add dev in-lb 192.168.20.2/24\ntc qdisc replace dev to-lb root sfq limit 100\n\nip netns exec lb netserver\n\nnetperf -H 192.168.20.2 -l 100 &\nnetperf -H 192.168.20.2 -l 100 &\nnetperf -H 192.168.20.2 -l 100 &\nnetperf -H 192.168.20.2 -l 100 &" } ], "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 - The vulnerable code is the SFQ qdisc, reached by configuring a qdisc via tc/netlink on a local netdevice and then driving local transmit traffic through it; there is no path for an unauthenticated remote peer to install the qdisc or control the requeue/limit conditions. Per kernel scoring convention, tc/qdisc netlink-configured subsystems are Local.\nAC:L - The attacker controls every precondition — SFQ limit, the veth/NAPI setup that forces NETDEV_TX_BUSY requeues into gso_skb, the number of flows, and the traffic rate — so the \"empty SFQ + inflated q.qlen + single-slot drop\" state is reached deterministically, as demonstrated by the upstream reproducer. No race window or uncontrollable memory layout is required.\nPR:L - Creating the veth pair and installing the SFQ qdisc requires only CAP_NET_ADMIN within a network namespace, which any unprivileged local user obtains via `unshare -Urn`; no real root in the init namespace is needed. Basic local user access is therefore sufficient.\nUI:N - The attacker sets up the qdisc and generates the traffic entirely on their own; no victim action, mount, or file open is involved.\nS:U - The corruption occurs in kernel memory and the resulting compromise stays within the same security authority (kernel/host); no VM, IOMMU, or hypervisor boundary is crossed.\nC:H - The stale q->tail leads to slot->qlen underflowing to 65535, causing sfq_link() to read q->dep[65535] roughly 256 KB out of bounds, and the emptied slot is returned as a fake sk_buff whose contents are read as skb->len/skb->data/GSO fields by the transmit path — both yield disclosure of adjacent kernel memory and, via heap grooming, arbitrary read.\nI:H - sfq_link() performs out-of-bounds writes (`q->dep[65535].next = x` and `sfq_dep_head(q, n)->prev = x` with n taken from out-of-bounds memory), and the type-confused sfq_slot is ultimately freed into skbuff_head_cache — an OOB write plus wild free that is leverageable for control-flow hijack and privilege escalation.\nA:H - Dequeuing from the stale empty slot reliably produces a bogus sk_buff handed to the device driver plus out-of-bounds accesses, causing kernel oops/panic (the reported symptom is a crash), and the condition can be re-triggered at will." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_sfq.c" ], "versions": [ { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "c337efb20d6d9f9bbb4746f6b119917af5c886dc", "status": "affected", "versionType": "git" }, { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "b44f791f27b14c9eb6b907fbe51f2ba8bec32085", "status": "affected", "versionType": "git" }, { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "5814a7fc3abb41f63f2d44c9d3ff9d4e62965b72", "status": "affected", "versionType": "git" }, { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "9c19498bdd7cb9d854bd3c54260f71cf7408495e", "status": "affected", "versionType": "git" }, { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "b4e9bab6011b9559b7c157b16b91ae46d4d8c533", "status": "affected", "versionType": "git" }, { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "d1bc80da75c789f2f6830df89d91fb2f7a509943", "status": "affected", "versionType": "git" }, { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "82448d4dcd8406dec688632a405fdcf7f170ec69", "status": "affected", "versionType": "git" }, { "version": "a53851e2c3218aa30b77abd6e68cf1c371f15afe", "lessThan": "82ffbe7776d0ac084031f114167712269bf3d832", "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_sfq.c" ], "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "lessThan": "4.16", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.295", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.239", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.186", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.142", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.94", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.34", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.3", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16", "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": "4.16", "versionEndExcluding": "5.4.295" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.10.239" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.15.186" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.1.142" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.6.94" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.12.34" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.15.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "6.16" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c337efb20d6d9f9bbb4746f6b119917af5c886dc" }, { "url": "https://git.kernel.org/stable/c/b44f791f27b14c9eb6b907fbe51f2ba8bec32085" }, { "url": "https://git.kernel.org/stable/c/5814a7fc3abb41f63f2d44c9d3ff9d4e62965b72" }, { "url": "https://git.kernel.org/stable/c/9c19498bdd7cb9d854bd3c54260f71cf7408495e" }, { "url": "https://git.kernel.org/stable/c/b4e9bab6011b9559b7c157b16b91ae46d4d8c533" }, { "url": "https://git.kernel.org/stable/c/d1bc80da75c789f2f6830df89d91fb2f7a509943" }, { "url": "https://git.kernel.org/stable/c/82448d4dcd8406dec688632a405fdcf7f170ec69" }, { "url": "https://git.kernel.org/stable/c/82ffbe7776d0ac084031f114167712269bf3d832" } ], "title": "net_sched: sch_sfq: fix a potential crash on gso_skb handling", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T17:34:18.395Z" } } ] } }