Erlang OTP up to 29.0.2 dtls_server_connection.erl random default key

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.69+

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Erlang OTP up to 4.2.0/8.1/11.7.2/19.x/29.0.2. This affects an unknown part in the library lib/ssl/src/dtls_server_connection.erl. The manipulation of the argument random leads to default key. This vulnerability is documented as CVE-2026-54887. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Erlang OTP up to 4.2.0/8.1/11.7.2/19.x/29.0.2 and classified as problematic. This issue affects an unknown functionality in the library lib/ssl/src/dtls_server_connection.erl. The manipulation of the argument random with an unknown input leads to a default key vulnerability. Using CWE to declare the problem leads to CWE-1394. The product uses a default cryptographic key for potentially critical functionality. The impact remains unknown. The summary by CVE is:

Use of Default Cryptographic Key vulnerability in Erlang/OTP ssl (DTLS server) allows predictable DTLS cookie computation during the startup window, enabling source address verification bypass. On DTLS server startup, dtls_server_connection:initial_hello/3 initializes previous_cookie_secret to the empty binary (>) instead of a random value. Because HMAC with an empty key is deterministic, anyone who observes the plaintext ClientHello can compute dtls_handshake:cookie(>, IP, Port, Hello) and forge a valid DTLS cookie before the first rotation of the cookie secret. The DTLS cookie (RFC 6347 §4.2.1) is a denial-of-service mitigation that prevents spoofed source IPs from forcing the server to allocate state and perform expensive cryptographic operations; it is not an authentication mechanism. During the window from server startup until the first secret rotation (0 to 15 seconds), an attacker who can observe the plaintext ClientHello can bypass the source address verification, enabling DTLS handshake amplification with spoofed source addresses. This vulnerability is associated with program file lib/ssl/src/dtls_server_connection.erl and program routine dtls_server_connection:initial_hello/3. This issue affects OTP from OTP 20.0 before 29.0.3, 28.5.0.3 and 27.3.4.14 corresponding to ssl from 8.2 before 11.7.3, 11.6.0.3 and 11.2.12.10.

The weakness was released by Lukas Backström. It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-54887 since 06/16/2026. The exploitation is known to be easy. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 4.2.1, 8.2, 11.2.12.10, 11.6.0.3, 11.7.3, 20.0, 27.3.4.14, 28.5.0.3 or 29.0.3 eliminates this vulnerability. Applying the patch 888e3bcd72d5406016b9e0de741026bc2a6f114d is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-41411). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Default key
CWE: CWE-1394
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: OTP 4.2.1/8.2/11.2.12.10/11.6.0.3/11.7.3/20.0/27.3.4.14/28.5.0.3/29.0.3
Patch: 888e3bcd72d5406016b9e0de741026bc2a6f114d

Timelineinfo

06/16/2026 CVE reserved
07/02/2026 +16 days Advisory disclosed
07/02/2026 +0 days VulDB entry created
07/02/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Researcher: Lukas Backström
Status: Confirmed

CVE: CVE-2026-54887 (🔒)
GCVE (CVE): GCVE-0-2026-54887
GCVE (VulDB): GCVE-100-375971
EUVD: 🔒

Entryinfo

Created: 07/02/2026 19:03
Updated: 07/02/2026 21:47
Changes: 07/02/2026 19:03 (57), 07/02/2026 21:47 (1)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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