Vulnerability · Published Oct 8, 2026 · Assigned by Go
CVE-2026-97031Reject malformed ECH outer extension references in crypto/tls
High 7.5
In plain English
A high-severity security flaw in crypto/tls from Go standard library. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 55.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | delve | 1.26.1-3.el10_2 | ALSA-2026:95519 |
| AlmaLinux:8 | delve | 1.26.1-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | delve | 1.26.1-2.el9_8 | ALSA-2026:95518 |
| AlmaLinux:10 | go-toolset | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | go-toolset | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | go-toolset | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-bin | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-bin | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-bin | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-docs | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-docs | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-docs | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-misc | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-misc | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-misc | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-race | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-race | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-race | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-src | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-src | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-src | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:10 | golang-tests | 1.26.10-1.el10_2.alma.1 | ALSA-2026:86093 |
| AlmaLinux:8 | golang-tests | 1.26.10-1.module_el8.10.0+4307+6e4cbc60 | ALSA-2026:86203 |
| AlmaLinux:9 | golang-tests | 1.26.10-1.el9_8 | ALSA-2026:86196 |
| AlmaLinux:8 | grafana | 9.2.10-36.el8_10 | ALSA-2026:88188 |
| AlmaLinux:9 | grafana | 10.2.6-23.el9_8.7 | ALSA-2026:89744 |
| AlmaLinux:10 | grafana-pcp | 5.3.0-8.el10_2.2 | ALSA-2026:88316 |
| AlmaLinux:8 | grafana-pcp | 5.1.1-19.el8_10 | ALSA-2026:88189 |
| AlmaLinux:9 | grafana-pcp | 5.1.1-17.el9_8.2 | ALSA-2026:88354 |
| AlmaLinux:8 | grafana-selinux | 9.2.10-36.el8_10 | ALSA-2026:88188 |
| AlmaLinux:9 | grafana-selinux | 10.2.6-23.el9_8.7 | ALSA-2026:89744 |
| AlmaLinux:10 | ipp-usb | 0.9.27-7.el10_2.4 | ALSA-2026:88280 |
| AlmaLinux:10 | opentelemetry-collector | 0.158.0-2.el10_2 | ALSA-2026:93596 |
| AlmaLinux:9 | opentelemetry-collector | 0.158.0-2.el9_8 | ALSA-2026:93617 |
| Alpine:v3.24 | go | 1.26.9-r0 | ALPINE-CVE-2026-97031 |
| Debian:12 | golang-1.19 | no fix listed | DEBIAN-CVE-2026-97031 |
| Debian:13 | golang-1.24 | no fix listed | DEBIAN-CVE-2026-97031 |
| Debian:14 | golang-1.26 | 1.26.9-1 | DEBIAN-CVE-2026-97031 |
| Debian:14 | golang-1.27 | 1.27.2-1 | DEBIAN-CVE-2026-97031 |
| Go | stdlib | 1.26.9, 1.27.2 | GO-2026-6607 |
| Rocky Linux:10 | delve | 0:1.26.1-3.el10_2 | RLSA-2026:95519 |
| Rocky Linux:8 | delve | 0:1.26.1-1.module+el8.10.0+40244+e7cb3ff8 | RLSA-2026:86203 |
| Rocky Linux:9 | delve | 0:1.26.1-2.el9_8 | RLSA-2026:95518 |
| Rocky Linux:10 | golang | 0:1.26.10-1.el10_2 | RLSA-2026:86093 |
| Rocky Linux:9 | golang | 0:1.26.10-1.el9_8 | RLSA-2026:86196 |
| Rocky Linux:10 | golang-github-openprinting-ipp-usb | 0:0.9.27-7.el10_2.4 | RLSA-2026:88280 |
| Rocky Linux:8 | grafana | 0:9.2.10-36.el8_10 | RLSA-2026:88188 |
| Rocky Linux:9 | grafana | 0:10.2.6-23.el9_8.7 | RLSA-2026:89744 |
| Rocky Linux:10 | grafana-pcp | 0:5.3.0-8.el10_2.2 | RLSA-2026:88316 |
| Rocky Linux:8 | grafana-pcp | 0:5.1.1-19.el8_10 | RLSA-2026:88189 |
| Rocky Linux:9 | grafana-pcp | 0:5.1.1-17.el9_8.2 | RLSA-2026:88354 |
| Rocky Linux:10 | opentelemetry-collector | 0:0.158.0-2.el10_2 | RLSA-2026:93596 |
| Rocky Linux:9 | opentelemetry-collector | 0:0.158.0-2.el9_8 | RLSA-2026:93617 |
| Ubuntu:22.04:LTS | golang-1.17 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:22.04:LTS | golang-1.18 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:22.04:LTS | golang-1.20 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:22.04:LTS | golang-1.21 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:24.04:LTS | golang-1.21 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:22.04:LTS | golang-1.23 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:24.04:LTS | golang-1.23 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:26.04:LTS | golang-1.23 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:22.04:LTS | golang-1.24 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:24.04:LTS | golang-1.24 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:26.04:LTS | golang-1.24 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:22.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:24.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:26.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:22.04:LTS | golang-1.26 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:24.04:LTS | golang-1.26 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:26.04:LTS | golang-1.26 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:26.10 | golang-1.26 | no fix listed | UBUNTU-CVE-2026-97031 |
| Ubuntu:26.10 | golang-1.27 | no fix listed | UBUNTU-CVE-2026-97031 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Go standard library | crypto/tls | 0 – before 1.26.91.27.0-0 – before 1.27.2 |
Weakness: CWE-405 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H