--- id: CVE-2026-81003 title: >- kernel: net/iucv: filter frames in afiucv_hs_rcv() by ingress device (CVE-2026-81003) summary: >- A flaw was found in the Linux kernel's AF_IUCV (Advanced Program-to-Program Communication over IUCV) network protocol implementation. The `afiucv_hs_rcv()` function, responsible for receiving frames, does not properly filter incoming frame… severity: high cvss: 7 cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H' cvssSource: vendor cwe: CWE-940 vendor: Red Hat product: Red Hat Enterprise Linux BaseOS (v. 9) affected: - enterprise_linux 10 - enterprise_linux 7 - enterprise_linux 8 - enterprise_linux 9 - openshift_container_platform 4 - enterprise_linux 6 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_9 patched: - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_v_9 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_9 published: '2026-09-11' updated: '2026-10-26' sourceUpdated: '2026-10-26T09:35:58+00:00' source: CSAF sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81003.json' references: - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81003.json - url: 'https://access.redhat.com/security/cve/CVE-2026-81003' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532515' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-81003' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81003' - url: >- https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-81003.mbox - url: 'https://access.redhat.com/errata/RHSA-2026:83156' - url: 'https://access.redhat.com/errata/RHSA-2026:89083' - url: 'https://git.kernel.org/stable/c/639828ad4d374056167391dbaffd13dd5e5e5ddb' - url: 'https://git.kernel.org/stable/c/92e5c281f1caa287bb58292f2687c9e3ff3aa23e' - url: 'https://git.kernel.org/stable/c/712330f8a4293cfd97b0d62b7c7dc01862a16b98' - url: 'https://git.kernel.org/stable/c/0a5af67e7184c6a0e155c317840bd64b37177af4' - url: 'https://git.kernel.org/stable/c/dfac2936b83be00035ae176f8252e1c1e1de9207' - url: 'https://git.kernel.org/stable/c/8e3763f1ccac3fc395f9af2b87114c023ced8a3f' - url: 'https://git.kernel.org/stable/c/a7f0130a091724e69827ab58e74777a88747e892' - url: 'https://git.kernel.org/stable/c/80230a18c164a4b5bbc048fe2768b219ac17bc5a' tags: - csaf - vex - red-hat - cve.org epss: 0.00309 epssPercentile: 0.23631 scores: vendor: 7 cna: 8.1 ingestedAt: '2026-09-14T15:23:07.454Z' --- ## Overview A flaw was found in the Linux kernel's AF_IUCV (Advanced Program-to-Program Communication over IUCV) network protocol implementation. The `afiucv_hs_rcv()` function, responsible for receiving frames, does not properly filter incoming frames based on the ingress network device. This oversight allows a local attacker with specific network capabilities or a host on the same HiperSockets segment to send specially crafted frames. Successful exploitation can lead to a Denial of Service (DoS) by exhausting the accept-queue, injecting data into existing sockets, and disrupting established connections. ## Vendor advisories - **RHSA-2026:83156** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-10-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:83156) - **RHSA-2026:89083** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:89083) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4, Red Hat Enterprise Linux 6 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81003.json) **kernel: net/iucv: filter frames in afiucv_hs_rcv() by ingress device** — rated Important by Red Hat. Released 2026-09-11, updated 2026-10-26. Affected: - Red Hat Enterprise Linux 10 - Red Hat Enterprise Linux 7 - Red Hat Enterprise Linux 8 - Red Hat Enterprise Linux 9 - Red Hat OpenShift Container Platform 4 - Red Hat Enterprise Linux 6 Fixed: - Red Hat Enterprise Linux AppStream (v. 9) - Red Hat Enterprise Linux BaseOS (v. 8) - Red Hat Enterprise Linux BaseOS (v. 9) - Red Hat Enterprise Linux CRB (v. 8) - Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) - Red Hat Enterprise Linux Real Time for NFV (v. 9) - Red Hat Enterprise Linux Real Time (v. 9) No fix planned: - Red Hat Enterprise Linux 10 - Red Hat Enterprise Linux 7 - Red Hat Enterprise Linux 8 - Red Hat Enterprise Linux 9 - Red Hat OpenShift Container Platform 4 ## Remediation For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associa… https://access.redhat.com/errata/RHSA-2026:83156 For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 The system must be rebooted for this update to take effect. Red Hat recommends treating all kernel errata as security-relevant. Given the kernel's fundamental role, any bug has a higher chance of impacting system security, even if that impact only becomes clear after a fix is published. Therefore, Red Hat prioritizes delivering fixes that improve our customers' overall security posture. Because of this proactive approach, a patch may be associa… https://access.redhat.com/errata/RHSA-2026:89083 Workarounds / mitigations: - Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.