Upstream information
Description
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.
SUSE information
Overall state of this security issue: Pending
This issue is currently rated as having important severity.
| CVSS detail | SUSE |
|---|---|
| Base Score | 7.5 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | None |
| Integrity Impact | None |
| Availability Impact | High |
| CVSSv3 Version | 3.1 |
| CVSS detail | CNA (6b3ad84c-e1a6-4bf7-a703-f496b71e49db) | SUSE |
|---|---|---|
| Base Score | 8.7 | 8.2 |
| Vector | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| Attack Vector | Network | Network |
| Attack Complexity | Low | Low |
| Attack Requirements | None | Present |
| Privileges Required | None | None |
| User Interaction | None | None |
| Vulnerable System Confidentiality Impact | None | None |
| Vulnerable System Integrity Impact | None | None |
| Vulnerable System Availability Impact | High | High |
| Subsequent System Confidentiality Impact | None | None |
| Subsequent System Integrity Impact | None | None |
| Subsequent System Availability Impact | None | None |
| CVSSv4 Version | 4.0 | 4.0 |
Status of this issue by product and package
Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.
| Product(s) | Source package | State |
|---|---|---|
| Products under general support and receiving all security fixes. | ||
| SUSE Linux Enterprise High Performance Computing 15 SP7 | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP7 | erlang | Not affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Server 16.0 | erlang | Affected |
| SUSE Linux Enterprise Server 16.1 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | erlang | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | erlang26 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | erlang | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | erlang | Affected |
| openSUSE Leap 16.0 | erlang | Affected |
| Products under Long Term Service Pack support and receiving important and critical security fixes. | ||
| SUSE Linux Enterprise High Performance Computing 15 SP4 | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | erlang | Not affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP4 | erlang | Not affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP5 | erlang | Not affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP6 | erlang | Not affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP6 | erlang26 | Affected |
| SUSE Linux Enterprise Server 15 SP4 | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP5 | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP6 | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP6 | erlang26 | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | erlang26 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | erlang | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | erlang26 | Affected |
| SUSE Manager Proxy 4.3 | erlang | Not affected |
| SUSE Manager Proxy LTS 4.3 | erlang | Not affected |
| SUSE Manager Retail Branch Server 4.3 | erlang | Not affected |
| SUSE Manager Retail Branch Server LTS 4.3 | erlang | Not affected |
| SUSE Manager Server 4.3 | erlang | Not affected |
| SUSE Manager Server LTS 4.3 | erlang | Not affected |
| Products past their end of life and not receiving proactive updates anymore. | ||
| SUSE Enterprise Storage 7 | erlang | Not affected |
| SUSE Enterprise Storage 7.1 | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | erlang | Not affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | erlang26 | Affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP2 | erlang | Not affected |
| SUSE Linux Enterprise Module for Server Applications 15 SP3 | erlang | Not affected |
| SUSE Linux Enterprise Real Time 15 SP2 | erlang | Not affected |
| SUSE Linux Enterprise Real Time 15 SP3 | erlang | Not affected |
| SUSE Linux Enterprise Real Time 15 SP4 | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP2 | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP3 | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | erlang | Not affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | erlang | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | erlang | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | erlang | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | erlang | Not affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | erlang | Not affected |
| SUSE Manager Proxy 4.1 | erlang | Not affected |
| SUSE Manager Proxy 4.2 | erlang | Not affected |
| SUSE Manager Retail Branch Server 4.1 | erlang | Not affected |
| SUSE Manager Retail Branch Server 4.2 | erlang | Not affected |
| SUSE Manager Server 4.1 | erlang | Not affected |
| SUSE Manager Server 4.2 | erlang | Not affected |
| openSUSE Leap 15.3 | erlang | Not affected |
| openSUSE Leap 15.4 | erlang | Not affected |
| openSUSE Leap 15.5 | erlang | Not affected |
| openSUSE Leap 15.6 | erlang | Not affected |
| openSUSE Leap 15.6 | erlang26 | Affected |
SUSE Timeline for this CVE
CVE page created: Thu Jul 2 20:05:26 2026CVE page last modified: Fri Jul 3 15:35:37 2026