GHSA-4H8F-FWPC-HWWF
Vulnerability from github – Published: 2026-09-29 18:31 – Updated: 2026-09-29 18:31Issue 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.
{
"affected": [],
"aliases": [
"CVE-2026-75806"
],
"database_specific": {
"cwe_ids": [
"CWE-1284"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-29T16:17:11Z",
"severity": "MODERATE"
},
"details": "Issue summary: An established DTLS 1.2 association using an AEAD cipher suite\ncan be terminated by a single unauthenticated datagram whose encrypted\nfragment is shorter than the mandatory explicit IV and authentication tag\noverhead.\n\nImpact summary: An attacker who can send a datagram that is routed to an\nexisting DTLS 1.2 association can tear that association down without knowing\nany key material. This is a Denial of Service limited to the targeted\nassociation. There is no memory safety or confidentiality impact.\n\nCWE: CWE-1284: Improper Validation of Specified Quantity in Input\n\nDescription: In TLS 1.2 and DTLS 1.2 every record protected by an AEAD cipher\nsuite carries an explicit IV followed by the ciphertext and an authentication\ntag. When decrypting such a record the record layer passed the record length to\nthe cipher implementation before checking that the record was long enough to\ncontain the explicit IV and the tag. For a record shorter than that overhead the\ncipher implementation rejected the impossible length, and the record layer\ntreated this as an internal failure and raised a fatal internal_error alert\ninstead of treating the record as one that failed authentication.\n\nIn TLS 1.2 the same record causes a fatal internal_error alert instead of the\nexpected bad_record_mac alert. Since any undecryptable record already\nterminates a TLS connection, this is a protocol conformance issue rather than\na security issue in TLS.\n\nThe fix validates the record length against the explicit IV and tag length\nbefore any AEAD processing, so that TLS reports bad_record_mac and DTLS\nsilently discards the record.\n\nFIPS impact: no\nThe affected code is outside the FIPS module boundary.",
"id": "GHSA-4h8f-fwpc-hwwf",
"modified": "2026-09-29T18:31:44Z",
"published": "2026-09-29T18:31:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-75806"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/04728a289a823e68137f88da016cb9ede307217d"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/050b275cd671a6eed1d6457642d41a5a77aab972"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/3a4589d015a9049d47b66f186cf50a8711343a1d"
},
{
"type": "WEB",
"url": "https://github.com/openssl/openssl/commit/5af82fefbaf2b5fec2fc0e1d87f112844902f01d"
},
{
"type": "WEB",
"url": "https://openssl-library.org/news/secadv/20260929.txt"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.