sentry-cli's glibc fails dns resolution in docker containers when IPv6 returns NXDOMAIN (even if ipv4 succeeds)

[aranair]

CLI Version

2.24.1, 3.3.1 (anything above 2.21.1 is broken but 2.21.1 works)

Operating System and Architecture

• macOS (arm64)
• macOS (x86_64)
• Linux (i686)
• Linux (x86_64)
• Linux (armv7)
• Linux (aarch64)
• Windows (i686)
• Windows (x86_64)

Operating System Version

Ubuntu 22.04

Link to reproduction repository

No response

CLI Command

sentry-cli releases new

Exact Reproduction Steps

• Run any EC2 instance in AWS (this is necessary)
• Start any docker image (e.g., alpine/ubuntu)
  • this step is also necessary; docker returns NXDOMAIN for missing record types
• DNS resolution for sentry.io returns the right address with IPv4 but returns NXDOMAIN for IPv6

$ docker run -it alpine sh
...
/ # host sentry.io
sentry.io has address 35.186.247.156
sentry.io has address 35.186.247.156
Host sentry.io not found: 3(NXDOMAIN)
Host sentry.io not found: 3(NXDOMAIN)

Try to create a sentry release, params don't matter -> dns resolution fails

sentry-cli ... releases new ...

This works if I run the docker container with --dns 8.8.8.8 (e.g., because the upstream resolver returns differently from AWS's)

Expected Results

Sentry-cli to create a release

Actual Results

CLI errors with a DNS resolution against sentry.io

error: API request failed
  caused by: [6] Couldn't resolve host name (Could not resolve host: sentry.io)

Logs

DEBUG   2026-03-10 16:57:31.637555109 +00:00 sentry-cli version: 2.24.1, platform: "linux", architecture: "x86_64"
...
  DEBUG   2026-03-10 16:57:31.639211567 +00:00 request POST https://sentry.io/api/0/projects/<redacted>
...
  DEBUG   2026-03-10 16:57:31.639345965 +00:00 retry number 0, max retries: 0
error: API request failed
  caused by: [6] Couldn't resolve host name (Could not resolve host: sentry.io)

[linear-code]

CLI-300

[szokeasaurusrex]

Hi @aranair, thank you for the bug report.

So that we can understand how urgent this issue is, have you been able to identify a suitable workaround for your use case? If I understand correctly, it seems like using --dns 8.8.8.8 is working for you?

[aranair]

Hi @aranair, thank you for the bug report.

So that we can understand how urgent this issue is, have you been able to identify a suitable workaround for your use case? If I understand correctly, it seems like using --dns 8.8.8.8 is working for you?

Not urgent, we found a separate workaround. We just ditched the official sentry GHA workflow which runs a docker container from ghcr, to running the cli from npx directly.