CVE-2026-53182

What it actually does

This flaw is a Linux kernel memory-corruption issue in the nl80211 Wi-Fi configuration interface. The parser for EMA RNR elements stores the number of parsed nested elements in an 8-bit count field, but without the corrected bounds check an oversized list can cause the count to exceed the representable range and become inconsistent with the allocation size used for the flexible array that stores parsed elements. A crafted nl80211 netlink request can therefore cause undersized allocation and out-of-bounds kernel memory access. Practical impact is most likely kernel crash/denial of service, with potential for local privilege escalation depending on kernel configuration, allocator behavior, hardening features, and attacker capabilities.

Why it matters to the business

Successful exploitation can destabilize Linux systems that use affected kernels and Wi-Fi/nl80211 functionality, potentially causing host crashes, service outages, or loss of availability for wireless access point, client, or embedded Linux devices. Because exploitation is not currently known to be public, EPSS is low, and the vulnerability is not in CISA KEV, immediate mass exploitation is unlikely; however, kernel memory-corruption bugs should still be prioritized on internet-facing wireless infrastructure, shared platforms, embedded appliances, and systems where untrusted users or containers may have network administration capabilities.

How an attack unfolds

An attacker first needs the ability to issue nl80211 netlink commands to the kernel, typically requiring local access with sufficient network-administration privilege such as CAP_NET_ADMIN or a service that can configure Wi-Fi settings on the attacker’s behalf. The attacker crafts a netlink message containing an oversized nested NL80211_ATTR_EMA_RNR_ELEMS list with more elements than the u8-backed count can safely represent. On an unpatched kernel, nl80211_parse_rnr_elems() may increment the count beyond its valid bound, allocate storage based on an incorrect count, and then process more parsed elements than the allocation safely supports. The resulting out-of-bounds kernel memory access can crash the system and, in favorable conditions, may be shaped into broader kernel memory corruption for privilege escalation. There is no indication from the provided data of active exploitation, ransomware use, or named threat-actor activity.

How to fix it

Apply a Linux kernel update from the operating system or device vendor that includes the fix to reject EMA RNR element lists once the count reaches 255. No specific affected product or fixed version was provided, so remediation should be performed through the relevant distribution, appliance, or embedded-device kernel advisory. Where immediate patching is not possible, reduce exposure by restricting local shell access, removing unnecessary CAP_NET_ADMIN privileges from users, services, and containers, avoiding privileged containers with network administration capabilities, limiting access to Wi-Fi management interfaces, and disabling or isolating unneeded wireless/AP functionality. Kernel hardening features such as KASLR, slab freelist hardening, hardened usercopy, and lockdown modes may reduce exploit reliability but should not be treated as a replacement for patching.

How to confirm the fix worked

Confirm the running kernel includes the vendor fix for the nl80211 EMA RNR bounds check, either by checking the installed kernel package against the vendor advisory or by verifying that the kernel source rejects nested NL80211_ATTR_EMA_RNR_ELEMS input when the RNR element count reaches 255. Validate that systems have rebooted into the patched kernel, since merely installing a kernel package is insufficient. Review container and service configurations to confirm CAP_NET_ADMIN is not granted unless required. For exposure testing, inventory systems with wireless hardware, AP functionality, hostapd/wpa_supplicant management paths, or nl80211 use, and verify they are running a fixed kernel. Avoid destructive proof-of-concept testing on production systems because triggering the issue may crash the kernel.

Typical attack path

1. Obtain local code execution or access to a component that can issue nl80211 Wi-Fi configuration commands.
2. Acquire or abuse network-administration capability, commonly CAP_NET_ADMIN, or a privileged Wi-Fi management service.
3. Construct a malformed nl80211 netlink request containing an oversized nested NL80211_ATTR_EMA_RNR_ELEMS attribute list.
4. Send the crafted request to the kernel through the nl80211 generic netlink interface.
5. Trigger incorrect element counting and allocation behavior in nl80211_parse_rnr_elems() on a vulnerable kernel.
6. Cause kernel memory corruption, resulting in denial of service or possible privilege escalation depending on exploit reliability and kernel hardening.

How to detect it

To determine whether exploitation may already have occurred, review kernel logs, persistent journal entries, crash dumps, and panic/oops records from wireless-capable systems for memory-corruption events near nl80211 or cfg80211 code paths. Useful sources include dmesg output, /var/log/kern.log, /var/log/messages, journalctl -k, kdump/vmcore data, kernel oops reports, KASAN/KFENCE reports, audit logs showing privileged netlink activity, and service logs for Wi-Fi management components such as hostapd, wpa_supplicant, NetworkManager, or custom controllers. Look for crashes shortly after unusual Wi-Fi configuration changes, AP/MBSSID/RNR/EMA operations, or processes with CAP_NET_ADMIN interacting with nl80211. Because no public exploit or unique network indicator is identified from the provided data, detection should focus on local kernel crash artifacts, suspicious use of network-administration capabilities, and anomalous netlink activity rather than remote network signatures.

• nl80211_parse_rnr_elems
• NL80211_ATTR_EMA_RNR_ELEMS
• cfg80211_rnr_elems
• KASAN: slab-out-of-bounds
• KASAN: out-of-bounds
• BUG: kernel NULL pointer dereference
• general protection fault
• kernel BUG at net/wireless/nl80211
• RIP: 0010:nl80211_parse_rnr_elems
• Call Trace: nl80211_parse_rnr_elems
• Call Trace: nl80211_set_beacon
• Call Trace: nl80211_start_ap
• hostapd
• wpa_supplicant
• NetworkManager

What your security team should do

• Prioritize patching Linux systems with Wi-Fi/AP functionality, embedded wireless devices, and systems where untrusted users or containers may hold CAP_NET_ADMIN.
• Confirm patched kernels are actually running after reboot, not merely installed.
• Remove CAP_NET_ADMIN and privileged-container settings from workloads that do not explicitly require them.
• Review hostapd, wpa_supplicant, NetworkManager, and custom Wi-Fi management services for unnecessary exposure to untrusted input or users.
• Monitor kernel logs for crashes or memory-corruption signatures involving nl80211, cfg80211, RNR, or EMA RNR parsing.
• Treat unexplained kernel panics on wireless-capable systems as potentially security-relevant until patched status and logs are reviewed.
• Track Linux distribution and appliance advisories for exact fixed kernel package versions because none were provided in the source data.