{"id":"CVE-2026-64531","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: reject oversized nested action attrs\n\nOpen vSwitch stores generated flow actions as nlattrs, whose nla_len\nfield is u16","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: reject oversized nested action attrs\n\nOpen vSwitch stores generated flow actions as nlattrs, whose nla_len\nfield is u16. Commit a1e64addf3ff (\"net: op…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2026-07-27","updated":"2026-08-01","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-64531","references":[{"url":"https://git.kernel.org/stable/c/1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3f1f755366687d051174739fb99f7d560202f60b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ab855641241387db062a5e41d9ad6b8561542572","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c66bd2626c2764f23764ff0f8277f44a9cfe8349","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d573250d228401f707f4dbc09d11227a6215ee5f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dbd14f736be02cfe73049bd801af89becd1a0749","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f1efff8858403191361a01269c6fe8dd7f55a385","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/28/8","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2026/07/31/17","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2026/08/01/1","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2026/08/01/3","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64531.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-64531"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2507402"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64531"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64531"},{"url":"https://lore.kernel.org/linux-cve-announce/2026072732-CVE-2026-64531-e4ce@gregkh/T"},{"url":"https://access.redhat.com/errata/RHSA-2026:56786"},{"url":"https://access.redhat.com/errata/RHSA-2026:56853"},{"url":"https://access.redhat.com/errata/RHSA-2026:57483"},{"url":"https://access.redhat.com/errata/RHSA-2026:57362"},{"url":"https://access.redhat.com/errata/RHSA-2026:53330"},{"url":"https://access.redhat.com/errata/RHSA-2026:51603"},{"url":"https://access.redhat.com/errata/RHSA-2026:51746"},{"url":"https://access.redhat.com/errata/RHSA-2026:53329"},{"url":"https://access.redhat.com/errata/RHSA-2026:59143"},{"url":"https://access.redhat.com/errata/RHSA-2026:59147"},{"url":"https://access.redhat.com/errata/RHSA-2026:59145"},{"url":"https://access.redhat.com/errata/RHSA-2026:59149"},{"url":"https://access.redhat.com/errata/RHSA-2026:51604"}],"tags":["nvd","exploit-available","csaf","vex","red-hat","cve.org"],"epss":0.0038,"epssPercentile":0.31825,"ingestedAt":"2026-08-01T21:14:39.364Z","exploits":{"github":4,"githubRepos":["https://github.com/HackSpeak/CVE-2026-64531","https://github.com/mahfuzreham/OVSwrap-CVE-2026-64531-Mitigation-Tool","https://github.com/0xBlackash/CVE-2026-64531"],"checkedAt":"2026-10-27T19:07:21.809Z"},"exploitAvailable":true,"vendor":"Red Hat","product":"Red Hat Enterprise Linux BaseOS E4S (v.9.4)","affected":["enterprise_linux 9","openshift_container_platform 4.14","openshift_container_platform 4.16","openshift_container_platform 4.18","openshift_container_platform 4.22","enterprise_linux_appstream_v_10","enterprise_linux_appstream_e4s_v_9_2","enterprise_linux_appstream_e4s_v_9_4","enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_10","enterprise_linux_baseos_e4s_v_9_2","enterprise_linux_baseos_e4s_v_9_4","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_v_10","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_real_time_for_nfv_v_10","enterprise_linux_real_time_for_nfv_e4s_v_9_2","enterprise_linux_real_time_for_nfv_e4s_v_9_4","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_real_time_v_10","enterprise_linux_real_time_e4s_v_9_2","enterprise_linux_real_time_e4s_v_9_4","enterprise_linux_real_time_v_9"],"patched":["openshift_container_platform 4.14","openshift_container_platform 4.16","openshift_container_platform 4.18","openshift_container_platform 4.22","enterprise_linux_appstream_v_10","enterprise_linux_appstream_e4s_v_9_2","enterprise_linux_appstream_e4s_v_9_4","enterprise_linux_appstream_v_9","enterprise_linux_baseos_v_10","enterprise_linux_baseos_e4s_v_9_2","enterprise_linux_baseos_e4s_v_9_4","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_v_10","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_real_time_for_nfv_v_10","enterprise_linux_real_time_for_nfv_e4s_v_9_2","enterprise_linux_real_time_for_nfv_e4s_v_9_4","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_real_time_v_10","enterprise_linux_real_time_e4s_v_9_2","enterprise_linux_real_time_e4s_v_9_4","enterprise_linux_real_time_v_9"],"cwe":["CWE-130"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:41:46.689802Z"},"slug":"CVE-2026-64531","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: reject oversized nested action attrs\n\nOpen vSwitch stores generated flow actions as nlattrs, whose nla_len\nfield is u16. Commit a1e64addf3ff (\"net: openvswitch: remove\nmisbehaving actions length check\") allowed the total sw_flow_actions\nstream to grow beyond 64 KiB, which is valid, but also removed the last\nguard preventing a generated nested action attribute from exceeding\nU16_MAX.\n\nAn oversized generated container can thus be closed with a truncated\nnla_len. A later dump or teardown then walks a structurally different\nstream than the one that was validated. In particular, an oversized\nnested CLONE/CT action may cause subsequent bytes in the generated\nstream to be interpreted as independent actions.\n\nKeep the larger total-action-stream behavior, but make nested action\nclose reject generated containers that do not fit in nla_len, and return\nthe error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and\nCHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse\nconstruction order before discarding failed wrappers, so resources copied\ninto the rejected tails are released before the wrappers are removed.\n\nMost failed outer wrappers are discarded by truncating actions_len after\nchild resources have been released. CHECK_PKT_LEN also trims its parent\nafter branch resources are gone. SET/TUNNEL close failures unwind their\nknown tun_dst ownership directly, and SET_TO_MASKED has no external\nownership and truncates on close failure.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:56786** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.14 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:56786)\n- **RHSA-2026:56853** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.16 · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:56853)\n- **RHSA-2026:57483** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.18 · released 2026-08-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:57483)\n- **RHSA-2026:57362** · Red Hat · fixed in: Red Hat OpenShift Container Platform 4.22 · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:57362)\n- **RHSA-2026:53330** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53330)\n- **RHSA-2026:51603** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-08-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:51603)\n- **RHSA-2026:51746** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) · released 2026-08-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:51746)\n- **RHSA-2026:53329** · 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 2026-08-11 · [advisory](https://access.redhat.com/errata/RHSA-2026:53329)\n- **RHSA-2026:59143** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 10) · released 2026-08-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:59143)\n- **RHSA-2026:59147** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-08-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:59147)\n- **RHSA-2026:59145** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS E4S (v.9.4) · released 2026-08-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:59145)\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-10-05 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64531.json)","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":5396,"id":"CVE-2026-64531","ts":1788887280016,"field":"exploit_available","old":"false","new":"true"},{"seq":4279,"id":"CVE-2026-64531","ts":1788886394041,"field":"exploit_available","old":"true","new":"false"},{"seq":3028,"id":"CVE-2026-64531","ts":1788883057673,"field":"exploit_available","old":"false","new":"true"},{"seq":2057,"id":"CVE-2026-64531","ts":1788882462142,"field":"exploit_available","old":"true","new":"false"},{"seq":1130,"id":"CVE-2026-64531","ts":1788881899145,"field":"exploit_available","old":"false","new":"true"}]}