CVE-2026-99133

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-99133", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.394Z", "datePublished": "2026-10-28T10:34:46.398Z", "dateUpdated": "2026-10-30T12:42:06.467Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:42:06.467Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/iucv: fix the recvmsg window update\n\niucv_sock_recvmsg() sends the HiperSockets-only AF_IUCV_FLAG_WIN without\ntesting the transport, so on a classic z/VM socket iucv_send_ctrl() sizes\nthe skb through a NULL iucv->hs_dev. SO_MSGLIMIT accepts 1, so msglimit / 2\nis zero and one recvmsg() on its own socket is enough for an unprivileged\nprocess to take a spurious disconnect.\n\nIt also calls iucv_send_ctrl() under spin_lock_bh(&message_q.lock), which\nallocates GFP_KERNEL inside a section the code treats as atomic. Sending\noutside that lock lets two recvmsg() reach afiucv_hs_send() at once, where\nmsg_recv is sampled for the advertised window and subtracted after\ndev_queue_xmit() -- and sendmsg reaches that counter under lock_sock()\nwhile recvmsg holds no socket lock, so both can subtract the same value,\nthe counter goes negative and the credit reaches the peer twice.\n\nTest the transport, claim the credit with atomic_xchg() after the last\nerror exit and hand it back if the transmit fails, and send once the lock\nis dropped."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/iucv/af_iucv.c"], "versions": [{"version": "3881ac441f642d56503818123446f7298442236b", "lessThan": "01123990f59ce32a1a5e690a4aeee002e932bb07", "status": "affected", "versionType": "git"}, {"version": "3881ac441f642d56503818123446f7298442236b", "lessThan": "1ebe68bbf8e75eeccaca0c7bc9694f5bc0c3f00a", "status": "affected", "versionType": "git"}, {"version": "3881ac441f642d56503818123446f7298442236b", "lessThan": "23e7fbbdca5aaba2a9a7bb9e4f2dc179c290ee76", "status": "affected", "versionType": "git"}, {"version": "3881ac441f642d56503818123446f7298442236b", "lessThan": "ce8aac3eb57f5366fa082b7cb8a1ac5652274f37", "status": "affected", "versionType": "git"}, {"version": "3881ac441f642d56503818123446f7298442236b", "lessThan": "8f2efa742f4cfe7dd756154f8bc07350dbe3ec92", "status": "affected", "versionType": "git"}, {"version": "3881ac441f642d56503818123446f7298442236b", "lessThan": "fe7393a627db2d093e8c0cae69d619b30fefae5f", "status": "affected", "versionType": "git"}, {"version": "3881ac441f642d56503818123446f7298442236b", "lessThan": "fa5acd038ea657ad5033713d6916214cbd349151", "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/iucv/af_iucv.c"], "versions": [{"version": "3.2", "status": "affected"}, {"version": "0", "lessThan": "3.2", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.161", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.115", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.59", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.13", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "3.2", "versionEndExcluding": "5.15.224"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.6.161"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.12.115"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "6.18.59"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "7.2.13"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.2", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/01123990f59ce32a1a5e690a4aeee002e932bb07"}, {"url": "https://git.kernel.org/stable/c/1ebe68bbf8e75eeccaca0c7bc9694f5bc0c3f00a"}, {"url": "https://git.kernel.org/stable/c/23e7fbbdca5aaba2a9a7bb9e4f2dc179c290ee76"}, {"url": "https://git.kernel.org/stable/c/ce8aac3eb57f5366fa082b7cb8a1ac5652274f37"}, {"url": "https://git.kernel.org/stable/c/8f2efa742f4cfe7dd756154f8bc07350dbe3ec92"}, {"url": "https://git.kernel.org/stable/c/fe7393a627db2d093e8c0cae69d619b30fefae5f"}, {"url": "https://git.kernel.org/stable/c/fa5acd038ea657ad5033713d6916214cbd349151"}], "title": "net/iucv: fix the recvmsg window update", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/iucv/af_iucv.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "01123990f59ce32a1a5e690a4aeee002e932bb07", "status": "affected", "version": "3881ac441f642d56503818123446f7298442236b", "versionType": "git"}, {"lessThan": "1ebe68bbf8e75eeccaca0c7bc9694f5bc0c3f00a", "status": "affected", "version": "3881ac441f642d56503818123446f7298442236b", "versionType": "git"}, {"lessThan": "23e7fbbdca5aaba2a9a7bb9e4f2dc179c290ee76", "status": "affected", "version": "3881ac441f642d56503818123446f7298442236b", "versionType": "git"}, {"lessThan": "ce8aac3eb57f5366fa082b7cb8a1ac5652274f37", "status": "affected", "version": "3881ac441f642d56503818123446f7298442236b", "versionType": "git"}, {"lessThan": "8f2efa742f4cfe7dd756154f8bc07350dbe3ec92", "status": "affected", "version": "3881ac441f642d56503818123446f7298442236b", "versionType": "git"}, {"lessThan": "fe7393a627db2d093e8c0cae69d619b30fefae5f", "status": "affected", "version": "3881ac441f642d56503818123446f7298442236b", "versionType": "git"}, {"lessThan": "fa5acd038ea657ad5033713d6916214cbd349151", "status": "affected", "version": "3881ac441f642d56503818123446f7298442236b", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/iucv/af_iucv.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "3.2"}, {"lessThan": "3.2", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.224", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.161", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.115", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.59", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.13", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "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\nnet/iucv: fix the recvmsg window update\n\niucv_sock_recvmsg() sends the HiperSockets-only AF_IUCV_FLAG_WIN without\ntesting the transport, so on a classic z/VM socket iucv_send_ctrl() sizes\nthe skb through a NULL iucv->hs_dev. SO_MSGLIMIT accepts 1, so msglimit / 2\nis zero and one recvmsg() on its own socket is enough for an unprivileged\nprocess to take a spurious disconnect.\n\nIt also calls iucv_send_ctrl() under spin_lock_bh(&message_q.lock), which\nallocates GFP_KERNEL inside a section the code treats as atomic. Sending\noutside that lock lets two recvmsg() reach afiucv_hs_send() at once, where\nmsg_recv is sampled for the advertised window and subtracted after\ndev_queue_xmit() -- and sendmsg reaches that counter under lock_sock()\nwhile recvmsg holds no socket lock, so both can subtract the same value,\nthe counter goes negative and the credit reaches the peer twice.\n\nTest the transport, claim the credit with atomic_xchg() after the last\nerror exit and hand it back if the transmit fails, and send once the lock\nis dropped."}], "id": "CVE-2026-99133", "lastModified": "2026-10-30T13:21:47.507", "metrics": {}, "published": "2026-10-28T11:17:33.147", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/01123990f59ce32a1a5e690a4aeee002e932bb07"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1ebe68bbf8e75eeccaca0c7bc9694f5bc0c3f00a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/23e7fbbdca5aaba2a9a7bb9e4f2dc179c290ee76"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8f2efa742f4cfe7dd756154f8bc07350dbe3ec92"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ce8aac3eb57f5366fa082b7cb8a1ac5652274f37"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fa5acd038ea657ad5033713d6916214cbd349151"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fe7393a627db2d093e8c0cae69d619b30fefae5f"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: kernel: Denial of Service via improper receive window handling in af_iucv", "id": "2562748", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2562748"}, "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-476", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nnet/iucv: fix the recvmsg window update\niucv_sock_recvmsg() sends the HiperSockets-only AF_IUCV_FLAG_WIN without\ntesting the transport, so on a classic z/VM socket iucv_send_ctrl() sizes\nthe skb through a NULL iucv->hs_dev. SO_MSGLIMIT accepts 1, so msglimit / 2\nis zero and one recvmsg() on its own socket is enough for an unprivileged\nprocess to take a spurious disconnect.\nIt also calls iucv_send_ctrl() under spin_lock_bh(&message_q.lock), which\nallocates GFP_KERNEL inside a section the code treats as atomic. Sending\noutside that lock lets two recvmsg() reach afiucv_hs_send() at once, where\nmsg_recv is sampled for the advertised window and subtracted after\ndev_queue_xmit() -- and sendmsg reaches that counter under lock_sock()\nwhile recvmsg holds no socket lock, so both can subtract the same value,\nthe counter goes negative and the credit reaches the peer twice.\nTest the transport, claim the credit with atomic_xchg() after the last\nerror exit and hand it back if the transmit fails, and send once the lock\nis dropped.", "A flaw was found in the Linux kernel's IUCV (Inter-User Communication Vehicle) networking subsystem. A local attacker can exploit this flaw to cause a Denial of Service (DoS) through a kernel crash or unexpected socket disconnection. The vulnerability is triggered when processing message receive requests without properly verifying the socket transport type or managing internal locks during receive window updates."], "name": "CVE-2026-99133", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "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": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-28T10:34:46Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-99133\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-99133\nhttps://git.kernel.org/stable/c/8f2efa742f4cfe7dd756154f8bc07350dbe3ec92\nhttps://git.kernel.org/stable/c/fa5acd038ea657ad5033713d6916214cbd349151\nhttps://git.kernel.org/stable/c/fe7393a627db2d093e8c0cae69d619b30fefae5f"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3881ac441f642d56503818123446f7298442236b,8f2efa742f4cfe7dd756154f8bc07350dbe3ec92)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3881ac441f642d56503818123446f7298442236b,fe7393a627db2d093e8c0cae69d619b30fefae5f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3881ac441f642d56503818123446f7298442236b,fa5acd038ea657ad5033713d6916214cbd349151)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "3.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,3.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.59,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.13,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3881ac441f642d56503818123446f7298442236b,8f2efa742f4cfe7dd756154f8bc07350dbe3ec92)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3881ac441f642d56503818123446f7298442236b,fe7393a627db2d093e8c0cae69d619b30fefae5f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3881ac441f642d56503818123446f7298442236b,fa5acd038ea657ad5033713d6916214cbd349151)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "3.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,3.2)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.59,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.13,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-28T11:45:09.958795+00:00", "updated": "2026-10-30T02:15:05.352329+00:00", "vendors": ["linux", "linux$PRODUCT$linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-476", "CWE-665", "CWE-682"]}