Bug 2507402 (CVE-2026-64531)
| Summary: | CVE-2026-64531 kernel: net: openvswitch: reject oversized nested action attrs | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | unspecified | CC: | akhatavk, akito5623, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in Open vSwitch in the Linux kernel. Improper handling of oversized nested action attributes can lead to a truncated length field, which could be exploited by a local attacker to alter kernel memory. This alteration might result in the disclosure of sensitive information or a local privilege escalation (LPE).
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Upstream advisory: https://lore.kernel.org/linux-cve-announce/2026072732-CVE-2026-64531-e4ce@gregkh/T Additional exploitability information: A public working local privilege escalation exploit and detailed technical write-up have been released. The researcher reports successful exploitation on multiple AlmaLinux 9/10 and CentOS Stream 9/10 releases. Technical report: https://heyitsas.im/posts/ovswrap/ Exploit: https://github.com/manizada/OVSwrap The RHEL 6 product status appears inconsistent.
Upstream identifies commit a1e64addf3ff ("net: openvswitch: remove misbehaving actions length check") as the vulnerability-introducing commit. This change was merged in 2025, while RHEL 7 is currently listed as Not affected because the vulnerable code is not present.
Could you please verify whether RHEL 6 is actually affected, or whether this is a product-status mapping error?
This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:51604 https://access.redhat.com/errata/RHSA-2026:51604 This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:51603 https://access.redhat.com/errata/RHSA-2026:51603 This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Via RHSA-2026:51746 https://access.redhat.com/errata/RHSA-2026:51746 This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:53330 https://access.redhat.com/errata/RHSA-2026:53330 This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:53329 https://access.redhat.com/errata/RHSA-2026:53329 This issue has been addressed in the following products: Red Hat Enterprise Linux 10 Via RHSA-2026:59143 https://access.redhat.com/errata/RHSA-2026:59143 This issue has been addressed in the following products: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Via RHSA-2026:59147 https://access.redhat.com/errata/RHSA-2026:59147 This issue has been addressed in the following products: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Via RHSA-2026:59145 https://access.redhat.com/errata/RHSA-2026:59145 This issue has been addressed in the following products: Red Hat Enterprise Linux 9 Via RHSA-2026:59149 https://access.redhat.com/errata/RHSA-2026:59149 This issue has been addressed in the following products: Red Hat OpenShift Container Platform 4.22 Via RHSA-2026:57362 https://access.redhat.com/errata/RHSA-2026:57362 This issue has been addressed in the following products: Red Hat OpenShift Container Platform 4.18 Via RHSA-2026:57483 https://access.redhat.com/errata/RHSA-2026:57483 This issue has been addressed in the following products: Red Hat OpenShift Container Platform 4.14 Via RHSA-2026:56786 https://access.redhat.com/errata/RHSA-2026:56786 This issue has been addressed in the following products: Red Hat OpenShift Container Platform 4.16 Via RHSA-2026:56853 https://access.redhat.com/errata/RHSA-2026:56853 |
In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject oversized nested action attrs Open vSwitch stores generated flow actions as nlattrs, whose nla_len field is u16. Commit a1e64addf3ff ("net: openvswitch: remove misbehaving actions length check") allowed the total sw_flow_actions stream to grow beyond 64 KiB, which is valid, but also removed the last guard preventing a generated nested action attribute from exceeding U16_MAX. An oversized generated container can thus be closed with a truncated nla_len. A later dump or teardown then walks a structurally different stream than the one that was validated. In particular, an oversized nested CLONE/CT action may cause subsequent bytes in the generated stream to be interpreted as independent actions. Keep the larger total-action-stream behavior, but make nested action close reject generated containers that do not fit in nla_len, and return the error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and CHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse construction order before discarding failed wrappers, so resources copied into the rejected tails are released before the wrappers are removed. Most failed outer wrappers are discarded by truncating actions_len after child resources have been released. CHECK_PKT_LEN also trims its parent after branch resources are gone. SET/TUNNEL close failures unwind their known tun_dst ownership directly, and SET_TO_MASKED has no external ownership and truncates on close failure.