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Vulnerability record · public intelligence
CVE-2026-18417
MEDIUM

Wild pointer dereference in Zephyr BSD sockets when a TCP listening socket reports an asynchronous error

Published Sep 28, 2026 · Updated Nov 3, 2026

Severity · CVSSMEDIUM · Not scored
Known exploitationNot listed
EPSS / likelihood0.18%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

Wild pointer dereference in Zephyr BSD sockets when a TCP listening socket reports an asynchronous error

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

The native BSD-socket layer recorded a pending asynchronous socket error by type-punning it into struct net_context's void user_data field (ctx->user_data = INT_TO_POINTER(-status) in zsock_accepted_cb(), zsock_received_cb(), zsock_connected_cb() and zsock_close_ctx() in subsys/net/lib/sockets/sockets_inet.c), reading it back with POINTER_TO_INT(). That same field is owned by the network stack for listening TCP contexts: net_tcp_accept() stores the parent context pointer there and the TCP core passes it back to the registered accept callback. A failed accept therefore left a small integer (an errno value) where the stack expected a struct net_context .

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
LOW
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. Patch commit ↗
  2. Security advisory ↗

Record history

Published Sep 28, 2026 · Last refreshed Nov 3, 2026