Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes DoS
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Partial Red Hat: 1 fixed, 11 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| OpenSSL | OpenSSL | 4.0.0 to before 4.0.3; 3.6.0 to before 3.6.5; 3.5.0 to before 3.5.9; 3.4.0 to before 3.4.8; 3.0.0 to before 3.0.23; 1.1.1 to before 1.1.1zj | 4.0.3, 3.6.5, 3.5.9, 3.4.8, 3.0.23, 1.1.1zj | Patch available | CNA |
- OpenSSL VendorOpenSSL Affected 4.0.0 to before 4.0.3; 3.6.0 to before 3.6.5; 3.5.0 to before 3.5.9; 3.4.0 to before 3.4.8; 3.0.0 to before 3.0.23; 1.1.1 to before 1.1.1zj Fixed in 4.0.3, 3.6.5, 3.5.9, 3.4.8, 3.0.23, 1.1.1zj Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* | 1.1.1 to before 1.1.1zj; 3.0.0 to before 3.0.23; 3.4.0 to before 3.4.8; 3.5.0 to before 3.5.9; 3.6.0 to before 3.6.5; 4.0.0 to before 4.0.3 | Vulnerable | OpenSSL |
- cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* Versions 1.1.1 to before 1.1.1zj; 3.0.0 to before 3.0.23; 3.4.0 to before 3.4.8; 3.5.0 to before 3.5.9; 3.6.0 to before 3.6.5; 4.0.0 to before 4.0.3 Vulnerable ·OpenSSL
Remediation
- Fix · CNA OpenSSL (OpenSSL) Fixed in 4.0.3, 3.6.5, 3.5.9, 3.4.8, 3.0.23, 1.1.1zj
Red Hat 2 advisories
- RHSA-2026:74166 Released 2026-09-30 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images openssl3-1:3.5.9-0.1.hum1@src, openssl3-devel-1:3.5.9-0.1.hum1@aarch64, openssl3-devel-1:3.5.9-0.1.hum1@x86_64 +4
- RHSA-2026:74162 Released 2026-09-30 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images openssl-1:3.5.9-0.1.hum1@aarch64, openssl-1:3.5.9-0.1.hum1@src, openssl-1:3.5.9-0.1.hum1@x86_64 +12
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
OpenSSL — openssl-library.org/news/secadv/20260929.txt
14 records Highest priority Priority MEDIUM 3 MEDIUM, 11 LOW
Other records, highest priority first
- TI-2026-58283 DTLS Retransmits Handshake Messages From a Stale Buffer OffsetPriority MEDIUM 43
- TI-2026-58285 QUIC: Unbounded RETIRE_CONNECTION_ID BacklogPriority MEDIUM 40
- TI-2026-39654 QUIC STREAM Fragment Metadata DoSPriority MEDIUM 40
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Developer Hub 1 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet |
| Red Hat JBoss Core Services | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | — |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
| Red Hat Satellite 6 | Affected | No fix yet: Fix deferred |
| Red Hat Hardened Images | Fixed | RHSA-2026:74162, RHSA-2026:74166 |
Not affected: 4 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Hardened Images
- Red Hat OpenShift AI (RHOAI)
Timeline
- 2026-10-02 Threatist record created from CVE-2026-75806
- 2026-10-03 Alias added: GHSA-4h8f-fwpc-hwwf
- 2026-10-16 Affected versions changed · Red Hat
- 2026-10-25 EPSS moved to the 50th–90th percentile
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-30 Affected versions changed · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
References
More Openssl vulnerabilities
- TI-2022-01915 The c_rehash script allows command injection CVSS 3.1CRITICAL 9.8
- TI-2021-02645 SM2 Decryption Buffer Overflow CVSS 3.1CRITICAL 9.8
- TI-2009-03392 The TLS protocol, and the SSL protocol 3.0 and possibly earlier, as used in Microsoft… CVSS 3.1CRITICAL 9.8
- TI-2022-01176 The c_rehash script allows command injection CVSS 3.1CRITICAL 9.8
- TI-2014-00154 The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly… KEVCVSS 3.1HIGH 7.5
- TI-2025-14107 Stack buffer overflow in CMS (Auth)EnvelopedData parsing CVSS 3.1HIGH 8.8
Sources
- CVE-2026-75806 · CVE Program
- CVE-2026-75806 · NVD
- FIRST EPSS
- GHSA-4h8f-fwpc-hwwf · GitHub Advisory Database · CC BY 4.0
- CVE-2026-75806 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences