CVE-2026-97031 (GCVE-0-2026-97031)
Vulnerability from cvelistv5 – Published: 2026-10-08 22:53 – Updated: 2026-10-08 22:53
VLAI
EPSS
VEX
Title
Reject malformed ECH outer extension references in crypto/tls
Summary
Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and curb the memory amplification vector as a result.
Severity
No CVSS data available.
CWE
- CWE-405 - Asymmetric Resource Consumption
Assigner
References
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Go standard library | crypto/tls |
Affected:
0 , < 1.26.9
(semver)
Affected: 1.27.0-0 , < 1.27.2 (semver) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "crypto/tls",
"product": "crypto/tls",
"programRoutines": [
{
"name": "decodeInnerClientHello"
},
{
"name": "Conn.Handshake"
},
{
"name": "Conn.HandshakeContext"
},
{
"name": "Conn.Read"
},
{
"name": "Conn.Write"
},
{
"name": "Dial"
},
{
"name": "DialWithDialer"
},
{
"name": "Dialer.Dial"
},
{
"name": "Dialer.DialContext"
},
{
"name": "QUICConn.Start"
}
],
"vendor": "Go standard library",
"versions": [
{
"lessThan": "1.26.9",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"lessThan": "1.27.2",
"status": "affected",
"version": "1.27.0-0",
"versionType": "semver"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and curb the memory amplification vector as a result."
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-405: Asymmetric Resource Consumption",
"lang": "en"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-08T22:53:58.775Z",
"orgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"shortName": "Go"
},
"references": [
{
"url": "https://go.dev/cl/847312"
},
{
"url": "https://go.dev/issue/81855"
},
{
"url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"
},
{
"url": "https://pkg.go.dev/vuln/GO-2026-6607"
}
],
"title": "Reject malformed ECH outer extension references in crypto/tls"
}
},
"cveMetadata": {
"assignerOrgId": "1bb62c36-49e3-4200-9d77-64a1400537cc",
"assignerShortName": "Go",
"cveId": "CVE-2026-97031",
"datePublished": "2026-10-08T22:53:58.775Z",
"dateReserved": "2026-09-23T23:03:36.988Z",
"dateUpdated": "2026-10-08T22:53:58.775Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"collectionURL": "https://pkg.go.dev",
"defaultStatus": "unaffected",
"packageName": "crypto/tls",
"product": "crypto/tls",
"programRoutines": [
{
"name": "decodeInnerClientHello"
},
{
"name": "Conn.Handshake"
},
{
"name": "Conn.HandshakeContext"
},
{
"name": "Conn.Read"
},
{
"name": "Conn.Write"
},
{
"name": "Dial"
},
{
"name": "DialWithDialer"
},
{
"name": "Dialer.Dial"
},
{
"name": "Dialer.DialContext"
},
{
"name": "QUICConn.Start"
}
],
"vendor": "Go standard library",
"versions": [
{
"lessThan": "1.26.9",
"status": "affected",
"version": "0",
"versionType": "semver"
},
{
"lessThan": "1.27.2",
"status": "affected",
"version": "1.27.0-0",
"versionType": "semver"
}
]
}
],
"source": "security@golang.org"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Multiple ECH outer extension references are not permitted under RFC 9849; previously, a client could send a well-crafted packet that could trigger memory exhaustion in the server process by specifying multiple references. We now reject these as malformed and curb the memory amplification vector as a result."
}
],
"id": "CVE-2026-97031",
"lastModified": "2026-10-08T23:17:06.037",
"metrics": {},
"published": "2026-10-08T23:17:06.037",
"references": [
{
"source": "security@golang.org",
"url": "https://go.dev/cl/847312"
},
{
"source": "security@golang.org",
"url": "https://go.dev/issue/81855"
},
{
"source": "security@golang.org",
"url": "https://groups.google.com/g/golang-announce/c/U2fTuyDJznI"
},
{
"source": "security@golang.org",
"url": "https://pkg.go.dev/vuln/GO-2026-6607"
}
],
"sourceIdentifier": "security@golang.org",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Important",
"current_release_date": "2026-10-08T23:25:03+00:00",
"cve": "CVE-2026-97031",
"id": "CVE-2026-97031",
"initial_release_date": "2026-10-08T22:53:58.775000+00:00",
"product_status:known_affected": "351",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97031.json",
"version": "3"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
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.
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.
Loading…
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.
Loading…