Skip to content

CVE-2026-55950

Time-of-check Time-of-use (TOCTOU): is CVE-2026-55950real, exploitable, or a false positive? Here's the community verdict.

signals

public sources

Exploited in wild
Not listed
CISA KEV
Public exploit
None known
Metasploit/EDB/PoC
Base severity
5.9 Medium
CVSS
Exploitation prob.
0.4%
FIRST EPSS
Weakness
CWE-367 · Time-of-check Time-of-use (TOCTOU)
CWE

Moderate signals. Triage by your actual exposure and reachability.

baseline read

auto · not a community verdict

Low signal — verdict needed

Few public signals point to active risk. Whether a scanner hit here is a true or false positive depends on your version and config — community verdicts decide.

Based on CVSS · FIRST EPSS

Confirm or dispute →

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Time-of-check Time-of-use (TOCTOU) race condition vulnerability in Erlang/OTP ssl (dtls_packet_demux module) allows an unauthenticated remote attacker to crash all active DTLS sessions on a listener. A DTLS server listener uses a single shared dtls_packet_demux gen_server process to route incoming UDP datagrams to the correct connection handler. When a DTLS client reconnects rapidly from the same source address and port (sending multiple ClientHello messages in quick succession), a race condition in the demux's internal gb_trees key-value store causes a {key_exists, {old, Client}} crash, terminating the demux process. Because the demux is shared across all DTLS associations on that listener, its crash immediately kills every active DTLS session, not just the attacker's. The attack is pre-authentication: the attacker only needs to send UDP datagrams containing valid ClientHello messages from the same source IP and port before the intermediate DOWN monitor message is processed by the gen_server. No credentials, no completed handshake, and no special configuration are required, and the crash can be repeated indefinitely to create a persistent denial of service for all clients of that listener. This vulnerability is associated with program file lib/ssl/src/dtls_packet_demux.erl. This issue affects OTP from OTP 25.3 before 29.0.3, 28.5.0.3, and 27.3.4.14 corresponding to ssl from 10.9 before 11.7.3, 11.6.0.3, and 11.2.12.10.

Published

Embed this verdict
TruePositive verdict for CVE-2026-55950
Markdown
[![TruePositive verdict](https://www.truepositive.app/cve/CVE-2026-55950/badge.svg)](https://www.truepositive.app/cve/CVE-2026-55950)
HTML
<a href="https://www.truepositive.app/cve/CVE-2026-55950"><img src="https://www.truepositive.app/cve/CVE-2026-55950/badge.svg" alt="TruePositive verdict for CVE-2026-55950"></a>

Live badge that updates automatically as the community verdict changes.

Community ground truth

Be the first practitioner to weigh in

So far this is only TruePositive's editorial baseline from public sources. Add your real-world verdict below — it becomes the signal the next person triaging this relies on.

🥇 The first 50 practitioners to contribute earn a Founding Contributor badge.

In your experience, is this finding real and exploitable?

0 verdicts
Not a real issue

No account needed. Anonymous verdicts post as an unverified signal. Log in to make yours verified and earn reputation.

Field notes & remediation

Verdicts are the quick signal. Notes are the evidence and fixes behind them.

No notes yet. Be the first to share what you saw, or a fix that worked.

    Add a field note or remediationoptional
    Note type

    What are you adding?

    Markdown supported · minimum 20 characters.

    Same weakness: CWE-367 · Time-of-check Time-of-use (TOCTOU).