{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38468", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.020Z", "datePublished": "2025-07-28T11:12:20.188Z", "dateUpdated": "2026-07-14T12:42:07.579Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T21:28:35.690Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: Return NULL when htb_lookup_leaf encounters an empty rbtree\n\nhtb_lookup_leaf has a BUG_ON that can trigger with the following:\n\ntc qdisc del dev lo root\ntc qdisc add dev lo root handle 1: htb default 1\ntc class add dev lo parent 1: classid 1:1 htb rate 64bit\ntc qdisc add dev lo parent 1:1 handle 2: netem\ntc qdisc add dev lo parent 2:1 handle 3: blackhole\nping -I lo -c1 -W0.001 127.0.0.1\n\nThe root cause is the following:\n\n1. htb_dequeue calls htb_dequeue_tree which calls the dequeue handler on\n the selected leaf qdisc\n2. netem_dequeue calls enqueue on the child qdisc\n3. blackhole_enqueue drops the packet and returns a value that is not\n just NET_XMIT_SUCCESS\n4. Because of this, netem_dequeue calls qdisc_tree_reduce_backlog, and\n since qlen is now 0, it calls htb_qlen_notify -> htb_deactivate ->\n htb_deactiviate_prios -> htb_remove_class_from_row -> htb_safe_rb_erase\n5. As this is the only class in the selected hprio rbtree,\n __rb_change_child in __rb_erase_augmented sets the rb_root pointer to\n NULL\n6. Because blackhole_dequeue returns NULL, netem_dequeue returns NULL,\n which causes htb_dequeue_tree to call htb_lookup_leaf with the same\n hprio rbtree, and fail the BUG_ON\n\nThe function graph for this scenario is shown here:\n 0) | htb_enqueue() {\n 0) + 13.635 us | netem_enqueue();\n 0) 4.719 us | htb_activate_prios();\n 0) # 2249.199 us | }\n 0) | htb_dequeue() {\n 0) 2.355 us | htb_lookup_leaf();\n 0) | netem_dequeue() {\n 0) + 11.061 us | blackhole_enqueue();\n 0) | qdisc_tree_reduce_backlog() {\n 0) | qdisc_lookup_rcu() {\n 0) 1.873 us | qdisc_match_from_root();\n 0) 6.292 us | }\n 0) 1.894 us | htb_search();\n 0) | htb_qlen_notify() {\n 0) 2.655 us | htb_deactivate_prios();\n 0) 6.933 us | }\n 0) + 25.227 us | }\n 0) 1.983 us | blackhole_dequeue();\n 0) + 86.553 us | }\n 0) # 2932.761 us | qdisc_warn_nonwc();\n 0) | htb_lookup_leaf() {\n 0) | BUG_ON();\n ------------------------------------------\n\nThe full original bug report can be seen here [1].\n\nWe can fix this just by returning NULL instead of the BUG_ON,\nas htb_dequeue_tree returns NULL when htb_lookup_leaf returns\nNULL.\n\n[1] https://lore.kernel.org/netdev/pF5XOOIim0IuEfhI-SOxTgRvNoDwuux7UHKnE_Y5-zVd4wmGvNk2ceHjKb8ORnzw0cGwfmVu42g9dL7XyJLf1NEzaztboTWcm0Ogxuojoeo=@willsroot.io/" } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sched/sch_htb.c" ], "versions": [ { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "fed3570e548a6c9f95c5f4c9e1a7afc1679fd90d", "status": "affected", "versionType": "git" }, { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "5c0506cd1b1a3b145bda2612bbf7fe78d186c355", "status": "affected", "versionType": "git" }, { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "850226aef8d28a00cf966ef26d2f8f2bff344535", "status": "affected", "versionType": "git" }, { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "890a5d423ef0a7bd13447ceaffad21189f557301", "status": "affected", "versionType": "git" }, { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "7ff2d83ecf2619060f30ecf9fad4f2a700fca344", "status": "affected", "versionType": "git" }, { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "e5c480dc62a3025b8428d4818e722da30ad6804f", "status": "affected", "versionType": "git" }, { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "3691f84269a23f7edd263e9b6edbc27b7ae332f4", "status": "affected", "versionType": "git" }, { "version": "512bb43eb5422ee69a1be05ea0d89dc074fac9a2", "lessThan": "0e1d5d9b5c5966e2e42e298670808590db5ed628", "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_htb.c" ], "versions": [ { "version": "2.6.29", "status": "affected" }, { "version": "0", "lessThan": "2.6.29", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.297", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.241", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.190", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.147", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.100", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.40", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.8", "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": "2.6.29", "versionEndExcluding": "5.4.297" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.29", "versionEndExcluding": "5.10.241" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.29", "versionEndExcluding": "5.15.190" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.29", "versionEndExcluding": "6.1.147" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.29", "versionEndExcluding": "6.6.100" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.29", "versionEndExcluding": "6.12.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.29", "versionEndExcluding": "6.15.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.29", "versionEndExcluding": "6.16" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/fed3570e548a6c9f95c5f4c9e1a7afc1679fd90d" }, { "url": "https://git.kernel.org/stable/c/5c0506cd1b1a3b145bda2612bbf7fe78d186c355" }, { "url": "https://git.kernel.org/stable/c/850226aef8d28a00cf966ef26d2f8f2bff344535" }, { "url": "https://git.kernel.org/stable/c/890a5d423ef0a7bd13447ceaffad21189f557301" }, { "url": "https://git.kernel.org/stable/c/7ff2d83ecf2619060f30ecf9fad4f2a700fca344" }, { "url": "https://git.kernel.org/stable/c/e5c480dc62a3025b8428d4818e722da30ad6804f" }, { "url": "https://git.kernel.org/stable/c/3691f84269a23f7edd263e9b6edbc27b7ae332f4" }, { "url": "https://git.kernel.org/stable/c/0e1d5d9b5c5966e2e42e298670808590db5ed628" } ], "title": "net/sched: Return NULL when htb_lookup_leaf encounters an empty rbtree", "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": "2025-11-03T17:38:33.418Z" } }, { "x_adpType": "supplier", "providerMetadata": { "orgId": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e", "shortName": "siemens-SADP", "dateUpdated": "2026-07-14T12:42:07.579Z" }, "affected": [ { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" }, { "vendor": "Siemens", "product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP", "versions": [ { "status": "affected", "version": "V3.1.5", "lessThan": "*", "versionType": "custom" } ], "defaultStatus": "unknown" } ], "references": [ { "url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html" } ] } ] } }