Vulnerability · Published May 7, 2026 · Assigned by Go
CVE-2026-39836Panic in Dial and LookupPort when handling NUL byte on Windows in net
High 7.5
In plain English
A high-severity security flaw in net 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 0.6% (higher than 51% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.6%top 49.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
The Dial and LookupPort functions panic on Windows when provided with an input containing a NUL (0).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | delve | 1.25.2-1.module_el8.10.0+4074+24330916 | ALSA-2026:22112 |
| AlmaLinux:8 | go-toolset | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | go-toolset | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| AlmaLinux:8 | golang | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | golang | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| AlmaLinux:8 | golang-bin | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | golang-bin | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| AlmaLinux:8 | golang-docs | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | golang-docs | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| AlmaLinux:8 | golang-misc | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | golang-misc | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| AlmaLinux:8 | golang-race | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | golang-race | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| AlmaLinux:8 | golang-src | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | golang-src | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| AlmaLinux:8 | golang-tests | 1.25.10-1.module_el8.10.0+4187+c45165c4 | ALSA-2026:22112 |
| AlmaLinux:9 | golang-tests | 1.26.3-1.el9_8 | ALSA-2026:22121 |
| Alpine:v3.23 | go | 1.25.10-r0 | ALPINE-CVE-2026-39836 |
| Alpine:v3.24 | go | 1.26.3-r0 | ALPINE-CVE-2026-39836 |
| Alpine:v3.24 | rclone | 1.74.1-r0 | ALPINE-CVE-2026-39836 |
| Go | stdlib | 1.25.10, 1.26.3 | GO-2026-4971 |
| Rocky Linux:8 | delve | 0:1.25.2-1.module+el8.10.0+40035+ee0a7047 | RLSA-2026:22112 |
| Rocky Linux:10 | golang | 0:1.26.3-4.el10_2 | RLSA-2026:22120 |
| Rocky Linux:8 | golang | 0:1.25.10-1.module+el8.10.0+40200+0fd0f175 | RLSA-2026:22112 |
| Rocky Linux:9 | golang | 0:1.26.3-1.el9_8 | RLSA-2026:22121 |
| Ubuntu:22.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-39836 |
| Ubuntu:24.04:LTS | golang-1.25 | no fix listed | UBUNTU-CVE-2026-39836 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Go standard library | net | 0 – before 1.25.101.26.0-0 – before 1.26.3 |