CVE-2026-97031CWE-405

CVE-2026-97031

High · published October 9, 2026

CVSS v3.1
7.5
EPSS
0%
Percentile
32.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00394 · 32.4th percentile
Weakness
CWE-405 · Asymmetric Resource Consumption (Amplification)
Published
2026-10-09T03:17Z
References (4)
https://go.dev/cl/847312 · [email protected]https://go.dev/issue/81855 · [email protected]https://groups.google.com/g/golang-announce/c/U2fTuyDJznI · [email protected]https://pkg.go.dev/vuln/GO-2026-6607 · [email protected]
EPSS history
Timeline
  • 10 OCT 03:32Z
    EPSS moved — → 0%
    epss
  • 08 OCT 22:53Z
    Reject malformed ECH outer extension references in crypto/tls
    cvelistv5
  • 08 OCT 22:53Z
    Reject malformed ECH outer extension references in crypto/tls
    cvelistv5