CVE-2026-74670

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-74670", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.925Z", "datePublished": "2026-08-22T15:32:40.850Z", "dateUpdated": "2026-08-25T05:41:25.343Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-25T05:41:25.343Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: stop estimator after disabled calc phase\n\nIPVS estimator kthread 0 starts with zeroed chain and tick limits until\nits initial calculation phase completes. If network namespace teardown\nclears ipvs->enable during that phase, ip_vs_est_calc_phase() can return\nwithout installing positive limits.\n\nThe kthread can then continue into its main loop and drain\nest_temp_list with zero chain_max, tick_max and est_max_count values.\nEach enqueue consumes one available tick row, but est_count never\nreaches the zero est_max_count value. After all rows are consumed, the\nrow lookup returns IPVS_EST_NTICKS and ip_vs_enqueue_estimator() writes\npast the ticks and tick_len arrays.\n\nExit kthread 0 after the calculation phase if the kthread is stopping or\nIPVS has been disabled. That keeps temporary estimators from being\ndrained after the limits failed to initialize.\n\nEstimator kthreads can now self-exit before teardown or reload stops\nkd->task. Keep an extra task reference after creation and release it\nwith kthread_stop_put(), so kd->task remains valid until the stop paths\nconsume that reference."}], "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 local IPVS configuration via netlink or setsockopt (GENL_ADMIN_PERM/CAP_NET_ADMIN); the bug is in estimator kthread management during namespace teardown, not in remote packet handling.\nAC:L - The attacker controls both sides of the race by creating a network namespace, adding many IPVS services to populate est_temp_list, and tearing down the namespace during kthread 0's calc phase.\nPR:L - Triggering IPVS service creation and namespace teardown requires CAP_NET_ADMIN, which unprivileged users can obtain in user+network namespaces via unshare on systems with unprivileged user namespaces enabled.\nUI:N - No victim interaction is required; an attacker can script IPVS service creation and namespace destruction without any action from another user or administrator.\nS:U - The out-of-bounds write corrupts kernel heap memory within the same kernel security boundary; impact is local privilege escalation or denial of service, not a cross-boundary escape.\nC:H - Out-of-bounds writes past ticks[] and tick_len[] corrupt adjacent heap metadata and kernel structures, providing a memory corruption primitive that can be leveraged for arbitrary kernel memory disclosure.\nI:H - Writing past the fixed-size ticks[] and tick_len[] arrays enables heap corruption that can overwrite function pointers or adjacent objects, supporting arbitrary kernel write and potential code execution.\nA:H - Heap corruption from unbounded index writes in ip_vs_enqueue_estimator() can cause kernel oops, panic, or hang when processing estimators after failed calc-phase initialization."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/netfilter/ipvs/ip_vs_est.c"], "versions": [{"version": "705dd34440812735ece298eb5bc153fde9544d42", "lessThan": "d5122a2b2601145975d387006e517c56896e310e", "status": "affected", "versionType": "git"}, {"version": "705dd34440812735ece298eb5bc153fde9544d42", "lessThan": "de98dc5ef94b83bbb444c670c253ea02ca0f5e43", "status": "affected", "versionType": "git"}, {"version": "705dd34440812735ece298eb5bc153fde9544d42", "lessThan": "e7f34f29b330265d456943bf0b984dcecfcef9af", "status": "affected", "versionType": "git"}, {"version": "705dd34440812735ece298eb5bc153fde9544d42", "lessThan": "2335dedc1922dfa889ca1f9f70370924e8e79a08", "status": "affected", "versionType": "git"}, {"version": "705dd34440812735ece298eb5bc153fde9544d42", "lessThan": "558f67f1340f803a346ecd14a69c49653111c5f4", "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/ipvs/ip_vs_est.c"], "versions": [{"version": "6.2", "status": "affected"}, {"version": "0", "lessThan": "6.2", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.152", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.104", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.9", "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": "6.2", "versionEndExcluding": "6.6.152"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.12.104"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "6.18.45"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "7.1.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.2", "versionEndExcluding": "7.2"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/d5122a2b2601145975d387006e517c56896e310e"}, {"url": "https://git.kernel.org/stable/c/de98dc5ef94b83bbb444c670c253ea02ca0f5e43"}, {"url": "https://git.kernel.org/stable/c/e7f34f29b330265d456943bf0b984dcecfcef9af"}, {"url": "https://git.kernel.org/stable/c/2335dedc1922dfa889ca1f9f70370924e8e79a08"}, {"url": "https://git.kernel.org/stable/c/558f67f1340f803a346ecd14a69c49653111c5f4"}], "title": "ipvs: stop estimator after disabled calc phase", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/netfilter/ipvs/ip_vs_est.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "d5122a2b2601145975d387006e517c56896e310e", "status": "affected", "version": "705dd34440812735ece298eb5bc153fde9544d42", "versionType": "git"}, {"lessThan": "de98dc5ef94b83bbb444c670c253ea02ca0f5e43", "status": "affected", "version": "705dd34440812735ece298eb5bc153fde9544d42", "versionType": "git"}, {"lessThan": "e7f34f29b330265d456943bf0b984dcecfcef9af", "status": "affected", "version": "705dd34440812735ece298eb5bc153fde9544d42", "versionType": "git"}, {"lessThan": "2335dedc1922dfa889ca1f9f70370924e8e79a08", "status": "affected", "version": "705dd34440812735ece298eb5bc153fde9544d42", "versionType": "git"}, {"lessThan": "558f67f1340f803a346ecd14a69c49653111c5f4", "status": "affected", "version": "705dd34440812735ece298eb5bc153fde9544d42", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/netfilter/ipvs/ip_vs_est.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.2"}, {"lessThan": "6.2", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.152", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.104", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.45", "versionType": "semver"}, {"lessThanOrEqual": "7.1.*", "status": "unaffected", "version": "7.1.9", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.2", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: stop estimator after disabled calc phase\n\nIPVS estimator kthread 0 starts with zeroed chain and tick limits until\nits initial calculation phase completes. If network namespace teardown\nclears ipvs->enable during that phase, ip_vs_est_calc_phase() can return\nwithout installing positive limits.\n\nThe kthread can then continue into its main loop and drain\nest_temp_list with zero chain_max, tick_max and est_max_count values.\nEach enqueue consumes one available tick row, but est_count never\nreaches the zero est_max_count value. After all rows are consumed, the\nrow lookup returns IPVS_EST_NTICKS and ip_vs_enqueue_estimator() writes\npast the ticks and tick_len arrays.\n\nExit kthread 0 after the calculation phase if the kthread is stopping or\nIPVS has been disabled. That keeps temporary estimators from being\ndrained after the limits failed to initialize.\n\nEstimator kthreads can now self-exit before teardown or reload stops\nkd->task. Keep an extra task reference after creation and release it\nwith kthread_stop_put(), so kd->task remains valid until the stop paths\nconsume that reference."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nipvs: detener el estimador despu\u00e9s de la fase de c\u00e1lculo deshabilitada\n\nEl kthread 0 del estimador de IPVS comienza con l\u00edmites de cadena y de tick puestos a cero hasta que su fase de c\u00e1lculo inicial se completa. Si la eliminaci\u00f3n del espacio de nombres de red borra ipvs -> enable durante esa fase, ip_vs_est_calc_phase() puede retornar sin instalar l\u00edmites positivos.\n\nEl kthread puede entonces continuar en su bucle principal y vaciar est_temp_list con valores de chain_max, tick_max y est_max_count puestos a cero. Cada encolamiento consume una fila de tick disponible, pero est_count nunca alcanza el valor de est_max_count puesto a cero. Despu\u00e9s de que todas las filas son consumidas, la b\u00fasqueda de fila retorna IPVS_EST_NTICKS e ip_vs_enqueue_estimator() escribe m\u00e1s all\u00e1 de los arrays de ticks y tick_len.\n\nSalir del kthread 0 despu\u00e9s de la fase de c\u00e1lculo si el kthread se est\u00e1 deteniendo o IPVS ha sido deshabilitado. Eso evita que los estimadores temporales sean vaciados despu\u00e9s de que los l\u00edmites no se inicializaron.\n\nLos kthreads del estimador ahora pueden auto-salir antes de que la eliminaci\u00f3n o recarga detenga kd -> task. Mantener una referencia de tarea adicional despu\u00e9s de la creaci\u00f3n y liberarla con kthread_stop_put(), para que kd -> task permanezca v\u00e1lido hasta que las rutas de detenci\u00f3n consuman esa referencia."}], "id": "CVE-2026-74670", "lastModified": "2026-10-14T13:10:00.187", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-08-22T16:16:40.953", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2335dedc1922dfa889ca1f9f70370924e8e79a08"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/558f67f1340f803a346ecd14a69c49653111c5f4"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d5122a2b2601145975d387006e517c56896e310e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/de98dc5ef94b83bbb444c670c253ea02ca0f5e43"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e7f34f29b330265d456943bf0b984dcecfcef9af"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: ipvs: stop estimator after disabled calc phase", "id": "2521449", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2521449"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-787", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nipvs: stop estimator after disabled calc phase\nIPVS estimator kthread 0 starts with zeroed chain and tick limits until\nits initial calculation phase completes. If network namespace teardown\nclears ipvs->enable during that phase, ip_vs_est_calc_phase() can return\nwithout installing positive limits.\nThe kthread can then continue into its main loop and drain\nest_temp_list with zero chain_max, tick_max and est_max_count values.\nEach enqueue consumes one available tick row, but est_count never\nreaches the zero est_max_count value. After all rows are consumed, the\nrow lookup returns IPVS_EST_NTICKS and ip_vs_enqueue_estimator() writes\npast the ticks and tick_len arrays.\nExit kthread 0 after the calculation phase if the kthread is stopping or\nIPVS has been disabled. That keeps temporary estimators from being\ndrained after the limits failed to initialize.\nEstimator kthreads can now self-exit before teardown or reload stops\nkd->task. Keep an extra task reference after creation and release it\nwith kthread_stop_put(), so kd->task remains valid until the stop paths\nconsume that reference.", "A flaw was found in the Linux kernel's IP Virtual Server (IPVS) component. During the initial setup of the IPVS estimator, if the network namespace is removed, the estimator may continue operating with uninitialized limits. This can lead to an out-of-bounds write when processing network statistics, potentially causing a system crash or denial of service."], "name": "CVE-2026-74670", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-22T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-74670\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74670\nhttps://lore.kernel.org/linux-cve-announce/2026082229-CVE-2026-74670-18f4@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[705dd34440812735ece298eb5bc153fde9544d42,d5122a2b2601145975d387006e517c56896e310e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[705dd34440812735ece298eb5bc153fde9544d42,de98dc5ef94b83bbb444c670c253ea02ca0f5e43)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[705dd34440812735ece298eb5bc153fde9544d42,e7f34f29b330265d456943bf0b984dcecfcef9af)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[705dd34440812735ece298eb5bc153fde9544d42,2335dedc1922dfa889ca1f9f70370924e8e79a08)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[705dd34440812735ece298eb5bc153fde9544d42,558f67f1340f803a346ecd14a69c49653111c5f4)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.152,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.104,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.45,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.1.9,7.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-08-22T17:45:02.902631+00:00", "title": "IPVS Estimator Kthread Memory Corruption During Namespace Teardown", "updated": "2026-08-25T10:15:04.111995+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-787"]}