CVE-2026-64531
HIGHnet: openvswitch: reject oversized nested action attrs
Title source: cnaExploitation Summary
EIP tracks 5 public exploits for CVE-2026-64531. PoCs published by HackSpeak, suominen, 0xBlackash.
AI-analyzed exploit summary This PoC exploits an integer wraparound vulnerability in the Linux kernel's Open vSwitch module (CVE-2026-64531) to achieve local privilege escalation (LPE) from an unprivileged user to root. The exploit leverages a 16-bit `nla_len` field overflow in nested action flows to gain arbitrary kernel read/write primitives, then manipulates task credentials to escalate privileges.
Description
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.
Exploits (5)
This PoC exploits an integer wraparound vulnerability in the Linux kernel's Open vSwitch module (CVE-2026-64531) to achieve local privilege escalation (LPE) from an unprivileged user to root. The exploit leverages a 16-bit `nla_len` field overflow in nested action flows to gain arbitrary kernel read/write primitives, then manipulates task credentials to escalate privileges.
This PoC exploits a Linux kernel vulnerability (CVE-2026-64531) in Open vSwitch's netlink handling to achieve local privilege escalation (LPE). The exploit manipulates OVS datapath and flow commands to corrupt kernel memory structures, leveraging pre-derived kernel offsets for precise control.
This repository provides a detailed technical tracker for CVE-2026-64531 (OVSwrap), a local privilege escalation vulnerability in the Linux kernel's Open vSwitch (OVS) datapath. The flaw involves an integer overflow in nested netlink action-attribute parsing, leading to heap out-of-bounds access and credential corruption. The writeup includes root cause analysis, patch details, affected versions, and distro-specific patch status tracking.
This repository provides a detailed technical analysis of CVE-2026-64531, a memory corruption vulnerability in the Linux Kernel Open vSwitch (OVS) subsystem. The writeup explains the root cause (incorrect validation of nested Netlink attribute sizes), affected components, and potential impact (DoS, potential LPE), but does not include exploit code.
This repository provides a mitigation tool (Bash script) for CVE-2026-64531, which detects and blocks the vulnerable Open vSwitch (OVS) kernel module. It does not exploit the vulnerability but prevents its exploitation by blacklisting and unloading the module.
References (11)
Scores
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H