CVE-2026-75806

Analyzed Analyzed - Analysis Complete

DTLS 1.2 Association Termination via Short Encrypted Datagram

Publication date: 2026-09-29

Last updated on: 2026-10-08

Assigner: OpenSSL Software Foundation

Description

Issue summary: An established DTLS 1.2 association using an AEAD cipher suite can be terminated by a single unauthenticated datagram whose encrypted fragment is shorter than the mandatory explicit IV and authentication tag overhead. Impact summary: An attacker who can send a datagram that is routed to an existing DTLS 1.2 association can tear that association down without knowing any key material. This is a Denial of Service limited to the targeted association. There is no memory safety or confidentiality impact. CWE: CWE-1284: Improper Validation of Specified Quantity in Input Description: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher suite carries an explicit IV followed by the ciphertext and an authentication tag. When decrypting such a record the record layer passed the record length to the cipher implementation before checking that the record was long enough to contain the explicit IV and the tag. For a record shorter than that overhead the cipher implementation rejected the impossible length, and the record layer treated this as an internal failure and raised a fatal internal_error alert instead of treating the record as one that failed authentication. In TLS 1.2 the same record causes a fatal internal_error alert instead of the expected bad_record_mac alert. Since any undecryptable record already terminates a TLS connection, this is a protocol conformance issue rather than a security issue in TLS. The fix validates the record length against the explicit IV and tag length before any AEAD processing, so that TLS reports bad_record_mac and DTLS silently discards the record. FIPS impact: no The affected code is outside the FIPS module boundary.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-29

Last Modified

2026-10-08

Generated

2026-10-19

AI Q&A

2026-09-29

EPSS Evaluated

2026-10-18

NVD

CVE-2026-75806

EUVD

EUVD-2026-89011

Affected Vendors & Products

Vendor	Product	Version / Range
openssl	openssl	From 3.4.0 (inc) to 3.4.8 (exc)
openssl	openssl	From 3.5.0 (inc) to 3.5.9 (exc)
openssl	openssl	From 3.6.0 (inc) to 3.6.5 (exc)
openssl	openssl	From 4.0.0 (inc) to 4.0.3 (exc)
openssl	openssl	From 1.1.1 (inc) to 1.1.1zj (exc)
openssl	openssl	From 3.0.0 (inc) to 3.0.23 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1284	The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

Attack-Flow Graph

Executive Summary

This vulnerability involves DTLS 1.2 associations using AEAD cipher suites. An attacker can send a single unauthenticated datagram with an encrypted fragment shorter than the required explicit IV and authentication tag. This causes the association to terminate without needing any key material, resulting in a Denial of Service limited to the targeted connection. No memory safety or confidentiality impact occurs.

Detection Guidance

Detecting this vulnerability requires monitoring for malformed TLS/DTLS AEAD records. Use network monitoring tools like Wireshark to inspect TLS/DTLS traffic for records shorter than the required explicit IV and authentication tag length. Check OpenSSL logs for SSL_AD_INTERNAL_ERROR alerts which may indicate exploitation attempts.

Impact Analysis

The impact is a Denial of Service where an attacker can terminate an existing DTLS 1.2 association by sending a malformed datagram. This disrupts the targeted connection but does not compromise data confidentiality or integrity.

Compliance Impact

This vulnerability primarily causes a Denial of Service (DoS) by terminating DTLS 1.2 associations without affecting confidentiality or memory safety. It does not directly violate GDPR or HIPAA requirements, as these standards focus on data protection and privacy rather than protocol-level DoS issues. However, repeated DoS attacks could indirectly impact compliance by disrupting services handling sensitive data.

Mitigation Strategies

Update OpenSSL to the latest patched version that includes the fix for CVE-2026-75806. If immediate patching is not possible, disable TLS 1.2 AEAD cipher suites temporarily as a workaround. Monitor network traffic for signs of exploitation attempts.

Hi! I’m here to help you understand CVE-2026-75806. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70