CVE-2026-55950 remediation guide

Erlang OTP, erlang/otp, erlang/ssl

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, te...

Open CVE record

ProductErlang OTP, erlang/otp, erlang/ssl

Affected versions>= 10.9, >= 25.3, >= 44dcb4c3d900777493ce2a6129f451aa475811f9 < e44d2bf01c4473ef2ea7f09e3523cf96de6e4a04, >= 25.3 < 27.3.4.14, >= 28.0 < 28.5.0.3, >= 29.0 < 29.0.3, >= 10.9 < 11.2.12.10, >= 11.3 < 11.6.0.3, >= 11.7 < 11.7.3

Fixed versions27.3.4.14, 28.5.0.3, 29.0.3, 11.2.12.10, 11.6.0.3, 11.7.3

Priority basisReview · CVSS 8.7 · EPSS 0.38%

Identify the affected asset

Confirm whether Erlang OTP, erlang/otp, erlang/ssl is installed, record the deployed version and installation path, and identify exposed interfaces.

Record the product name, package or appliance identifier, and installed version.
Identify internet-facing, administrative, API, and internal access paths.
Preserve the pre-change configuration and relevant service logs.

Validate the affected-version match

Compare the deployed version with the affected range: >= 10.9, >= 25.3, >= 44dcb4c3d900777493ce2a6129f451aa475811f9 < e44d2bf01c4473ef2ea7f09e3523cf96de6e4a04, >= 25.3 < 27.3.4.14, >= 28.0 < 28.5.0.3, >= 29.0 < 29.0.3, >= 10.9 < 11.2.12.10, >= 11.3 < 11.6.0.3, >= 11.7 < 11.7.3. Treat incomplete inventory results as unresolved.

Prioritize with independent signals

The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.

Apply supported remediation

Follow the vendor advisory or supported update path. Current fixed-version status: 27.3.4.14, 28.5.0.3, 29.0.3, 11.2.12.10, 11.6.0.3, 11.7.3. Preserve configuration and rollback material before change.

Verify the result

Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.

Confirm the expected version and package state.
Run a functional health check for critical service paths.
Review authentication, error, application, and security monitoring logs.
Reassess exposure if the supported fix cannot be applied.

Operational boundary

This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.