CVE-2021-29504: 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 ...

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.

Metrics

CVSS 3.1

7.4/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

1.31%

67.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-295

Affected Software

Vendor	Product	Versions
Wp-Cli	Wp-Cli	>= 0.12.0, < 2.5.0

References

https://github.com/wp-cli/checksum-command/pull/86Patch, Third Party Advisory
https://github.com/wp-cli/config-command/pull/128Patch, Third Party Advisory
https://github.com/wp-cli/core-command/pull/186Patch, Third Party Advisory
https://github.com/wp-cli/extension-command/pull/287Patch, Third Party Advisory
https://github.com/wp-cli/package-command/pull/138Third Party Advisory
https://github.com/wp-cli/wp-cli/pull/5523Patch, Third Party Advisory
https://github.com/wp-cli/wp-cli/security/advisories/GHSA-rwgm-f83r-v3qjThird Party Advisory
https://github.com/wp-cli/checksum-command/pull/86Patch, Third Party Advisory
https://github.com/wp-cli/config-command/pull/128Patch, Third Party Advisory
https://github.com/wp-cli/core-command/pull/186Patch, Third Party Advisory
https://github.com/wp-cli/extension-command/pull/287Patch, Third Party Advisory
https://github.com/wp-cli/package-command/pull/138Third Party Advisory
https://github.com/wp-cli/wp-cli/pull/5523Patch, Third Party Advisory
https://github.com/wp-cli/wp-cli/security/advisories/GHSA-rwgm-f83r-v3qjThird Party Advisory

Timeline

Published: Jun 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-29504?

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.

How severe is CVE-2021-29504?

CVE-2021-29504 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 1.31% probability of exploitation in the next 30 days.

How do I fix CVE-2021-29504?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.