CVE-2026-102165

Executive Summary

CVE-2026-102165 is a stack-based buffer overflow (CWE-121) in the capture service of affected Arista Wi-Fi access points. An unauthenticated attacker with adjacency to the device's network can send a crafted packet that crashes the service or potentially achieves remote code execution, provided an uncommonly used non-default streaming mode is enabled. The vulnerability carries a CVSS v3.1 base score of 7.5 and remains unpatched as of this report, with no public proof-of-concept or known exploitation in the wild.

Technical Analysis

The flaw resides in a network-facing capture service running on Arista Wi-Fi access points. Per the NVD description, the service fails to correctly bound input when processing a crafted packet, resulting in a stack-based buffer overflow. CWE-121 specifically denotes improper neutralization of length or size in a stack-allocated buffer, meaning attacker-controlled data is written past the end of a fixed-length stack buffer, overwriting adjacent stack memory (including saved control-flow data such as return addresses or saved frame pointers).

The attack surface is the capture service's packet-processing path. The precondition of network access to that service classifies the vector as adjacent (AV:A) rather than fully network-exploitable, because the attacker must reach the service over an adjacent network segment — typical of the management or data plane reachable from within Wi-Fi or local L2/L3 proximity.

Two factors shape exploitability:

• Configuration-dependent exposure: the vulnerable code path is only reachable when an "uncommonly used non-default streaming mode" is enabled. Deployments that leave this mode disabled are not exposed, which narrows the affected population and explains the High attack complexity (AC:H) rating — successful exploitation requires the target to be in a specific non-default state.
• Impact class: the CVSS subscores are Confidentiality/Integrity/Availability all High (C:H/I:H/A:H). The overflow can corrupt control flow, enabling potential remote code execution, with the more immediate and reliable outcome being a crash (denial of service) of the capture service. Whether code execution is reliably achievable depends on memory protections (ASLR, stack canaries, NX) on the device platform and the attacker's control over the overwritten bytes — details not disclosed in the advisory.

Because the vulnerable component is a service on the access point itself (not a management endpoint on an upstream controller), the immediate fault domain is the AP. However, if the capture service participates in infrastructure workflows (wireless troubleshooting, packet capture forwarding to a controller or collector), a crash or compromise can disrupt monitoring visibility and may expose captured traffic processed by the device.

Exploitation Scenarios

No public PoC is available; the attack chain below is inferred strictly from the vulnerability class and the NVD description, and no unverified function names, endpoints, or parameter names are asserted.

1. Reconnaissance / target identification. The attacker identifies reachable Arista Wi-Fi access points from an adjacent network segment. This may involve scanning for hosts exposing the capture service, or identifying APs via authenticated wireless association or management segment access. The attacker must have L2/L3 adjacency to the device.
2. Trigger condition assessment. The attacker needs the target to have the non-default streaming mode enabled. Since this mode is uncommon and off by default, opportunistic mass exploitation is unlikely; exploitation is targeted at environments known to enable this mode (for example, deployment-specific capture or telemetry workflows).
3. Vulnerability-class trigger. The attacker constructs a crafted packet delivering an over-length or malformed field to the capture service's parsing routine. Because of the stack buffer overflow, the oversized input overruns the stack frame rather than being safely truncated or rejected. No authentication is required (PR:N) and no user interaction is needed (UI:N).
4. Payload / execution method. At the vulnerability-class level, exploitation proceeds by controlling the overwritten stack memory. The typical escalation is: (a) immediate DoS via corrupted control flow causing a service crash, or (b) code execution by overwriting a saved return address or equivalent control datum with a value that redirects execution into attacker-influenced memory. The specific offsets, gadget availability, and mitigations are platform-specific and not disclosed.
5. Post-exploitation impact. A successful RCE yields code execution with the privileges of the capture service on the AP. An AP compromise can enable traffic inspection, lateral movement into the wireless infrastructure management plane, persistent foothold on the device, and disruption of the wireless service. A crash confines impact to service availability (a single-vector DoS against the capture service).

Impact Assessment

• Base score: 7.5 (High), driven by High availability, confidentiality, and integrity impact with an adjacent attack vector and high complexity.
• Attack vector (AV:A) and complexity (AC:H): exploitation requires network adjacency plus the non-default streaming mode, reducing the opportunity for opportunistic attackers — but not eliminating targeted risk, since conditions are deterministic once known.
• Privileges (PR:N) and user interaction (UI:N): no credentials and no user action are needed once the service is reachable and the streaming mode is active, making the flaw attractive for unauthenticated intrusion.
• Blast radius: internetwork exposure is limited by adjacency, but a compromised AP serves as a network choke point. A successful RCE gives an attacker a position on the wireless edge, from which wireless client traffic may be observed or redirected and internal management paths may be probed.
• Availability impact: the most probable outcome is a crash of the capture service, degrading packet-capture and monitoring reliability. If the service is required for operational diagnostics, repeated triggering could impair incident response visibility.

Detection Guidance

Sigma Rule

title: Potential Arista Wi-Fi Capture Service Stack Buffer Overflow (CVE-2026-102165)
id: 8f3c1a92-7b4e-4d21-9a6e-cve2026102165
status: experimental
description: Detects crashes or abnormal termination of the Arista Wi-Fi access point capture service, indicative of exploitation of a crafted-packet stack-based buffer overflow.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-102165
author: valtersit.com
date: 2026/01/01
logsource:
  category: application
  product: linux
detection:
  selection_service:
    process.name|contains:
      - 'capture'
  selection_crash:
    message|contains|all:
      - 'segfault'
  condition: selection_service and selection_crash
level: high

YARA Rule

rule CVE_2026_102165_Arista_Capture_BufferOverflow
{
    meta:
        description = "Detects anomalous stack-smashing artifacts or crash strings associated with CVE-2026-102165 capture service overflow"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-102165"
        date = "2026-01-01"
        severity = "high"
    strings:
        $stack_chk = "*** stack smashing detected ***"
        $segv = "segmentation fault"
        $svc = "capture service" nocase
    condition:
        ($stack_chk or $segv) and $svc
}

Suricata IDS Rule

alert udp any any -> any any (msg:"CVE-2026-102165 Potential Arista Wi-Fi Capture Service Buffer Overflow Attempt"; flow:to_server; content:"|00 00|"; depth:2; dsize:>1400; threshold:type limit, track by_src, count 1, seconds 60; classtype:attempted-admin; reference:cve,2026-102165; sid:2026102165; rev:1;)

Elastic Detection

process where process.name : "capture*" and
  process.exit_code != 0 and
  message like~ "*stack smashing*" or message like~ "*segmentation fault*"

Splunk SPL Query

index=wifi_appliance sourcetype=syslog
| search "capture service" (segfault OR "stack smashing" OR "signal 11" OR "buffer overflow")
| stats count min(_time) as first_seen max(_time) as last_seen values(src) as srcs by host
| where count >= 1

Wazuh OSSEC Rule

<group name="arista,cve-2026-102165,">
  <rule id="2026103" level="12">
    <decoded_as>syslog</decoded_as>
    <match>capture service</match>
    <regex>stack smashing|segmentation fault|signal 11|buffer overflow</regex>
    <description>CVE-2026-102165 possible Arista Wi-Fi capture service crash/overflow attempt</description>
    <mitre>
      <id>T1190</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source).

1. Immediate mitigations:
   • Disable the non-default streaming mode referenced in the advisory on all Arista Wi-Fi access points. Because the vulnerable path is only reachable in this uncommon mode, disabling it removes the attack surface.
   • Restrict network access to the capture service to trusted management segments using ACLs, segmentation, or firewall rules so that only authorized adjacent hosts can reach it.
   • Monitor for service crashes and stack-smashing artifacts as an early indicator of exploitation attempts.
2. Patch/upgrade steps: No vendor patch is currently evidenced. Monitor Arista's official security advisory channel and apply the vendor-released fix as soon as it becomes available. Track the CVE record at NVD for updates.
3. Long-term hardening:
   • Compile/harden the service platform with stack canaries, ASLR, and non-executable stack where the vendor supports it.
   • Adopt a wireless infrastructure patch-management process with SLA-driven timelines for critical access-point firmware.
   • Enforce least-privilege management-plane segmentation for all wireless infrastructure, preventing arbitrary hosts on the wireless or data network from reaching control services.

References

• NVD — CVE-2026-102165: https://nvd.nist.gov/vuln/detail/CVE-2026-102165
• MITRE CWE-121 (Stack-based Buffer Overflow): https://cwe.mitre.org/data/definitions/121.html
• MITRE ATT&CK T1190 (Exploit Public-Facing Application): https://attack.mitre.org/techniques/T1190/
• Arista Security Advisories (vendor channel — monitor for the corresponding advisory): https://www.arista.com/en/support/advisories-notices

No CISA KEV listing, no public PoC, and no confirmed in-the-wild exploitation were identified in the available data at the time of this report.