{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72436", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.929Z", "datePublished": "2026-08-15T05:56:50.051Z", "dateUpdated": "2026-08-17T05:44:12.018Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:44:12.018Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types\n\nSashiko pointed out that there are a few lockless RCU readers\nusing test_bit() which is a relaxed atomic operation and\nprovides no memory barrier guarantees. Use test_bit_acquire()\ninstead where the operation may run parallel with add/del/gc,\ni.e. is not one from the next cases\n\n- protected by region lock\n- in a set destroy phase\n- in a new/temporary set creation phase" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable mtype_test() runs on every packet matched by iptables/nftables xt_set rules in PREROUTING/INPUT/FORWARD, so a remote attacker reaches the bug by sending network traffic to internet-facing servers using ipset-based firewall blocklists.\nAC:L - The attacker controls both sides of the race by flooding packets that trigger lockless RCU readers while concurrently driving hash add/del via SET target rules or timeout GC on the same ipset, making the memory-ordering race reliably winnable.\nPR:N - No credentials or local access are required on the target; exploitation needs only unauthenticated network packets to a host running ipset netfilter rules, a standard deployment on firewalls, mail servers, and CDN edge nodes.\nUI:N - No victim interaction is needed; the attack is fully automated by sending network traffic and does not require mounting filesystems, opening files, or any other user action.\nS:U - The vulnerability corrupts or leaks kernel heap data within the same host security boundary; it does not cross VM, container, or IOMMU isolation boundaries.\nC:H - Without acquire semantics, test_bit() can observe a slot as used before element writes are visible or after deletion, causing reads of uninitialized, stale, or freed hbucket element and extension memory—a UAF-class kernel information disclosure.\nI:H - Stale or torn reads of hash bucket elements during concurrent add/del/gc constitute kernel heap memory safety violations that can corrupt netfilter matching decisions and be further leveraged for control-flow or data manipulation attacks.\nA:H - Reading partially initialized or post-destroy hash element memory during softirq packet processing on loaded firewall datapaths can trigger kernel oopses, panics, or hangs, causing complete loss of availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/netfilter/ipset/ip_set_hash_gen.h" ], "versions": [ { "version": "18f84d41d34fa35d0d64bbaea01fe664553ecc06", "lessThan": "c107233d2ff4fd7cef5d02f9124b99194957a710", "status": "affected", "versionType": "git" }, { "version": "18f84d41d34fa35d0d64bbaea01fe664553ecc06", "lessThan": "6329d3a9afe715fddda0460cfa46b496d61c2fe0", "status": "affected", "versionType": "git" }, { "version": "18f84d41d34fa35d0d64bbaea01fe664553ecc06", "lessThan": "7445fe965b7d8756070a40e80f8b73348ccda1d7", "status": "affected", "versionType": "git" }, { "version": "18f84d41d34fa35d0d64bbaea01fe664553ecc06", "lessThan": "c4d257734e91bfcdc71d41843392dd6400b5bb1b", "status": "affected", "versionType": "git" }, { "version": "18f84d41d34fa35d0d64bbaea01fe664553ecc06", "lessThan": "3219d74e4536658c937fd878a327257b86ce80dd", "status": "affected", "versionType": "git" }, { "version": "18f84d41d34fa35d0d64bbaea01fe664553ecc06", "lessThan": "e4b4984e28c16406ecb318444dea4a8bf47def3e", "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/netfilter/ipset/ip_set_hash_gen.h" ], "versions": [ { "version": "4.2", "status": "affected" }, { "version": "0", "lessThan": "4.2", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "4.2", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.2", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/c107233d2ff4fd7cef5d02f9124b99194957a710" }, { "url": "https://git.kernel.org/stable/c/6329d3a9afe715fddda0460cfa46b496d61c2fe0" }, { "url": "https://git.kernel.org/stable/c/7445fe965b7d8756070a40e80f8b73348ccda1d7" }, { "url": "https://git.kernel.org/stable/c/c4d257734e91bfcdc71d41843392dd6400b5bb1b" }, { "url": "https://git.kernel.org/stable/c/3219d74e4536658c937fd878a327257b86ce80dd" }, { "url": "https://git.kernel.org/stable/c/e4b4984e28c16406ecb318444dea4a8bf47def3e" } ], "title": "netfilter: ipset: Don't use test_bit() in lockless RCU readers in hash types", "x_generator": { "engine": "bippy-1.2.0" } } } }