What is CVE-2021-37704?

CVE-2021-37704 is a medium-severity security vulnerability in phpfastcache/phpfastcache (composer), affecting versions < 6.1.5. It is fixed in 6.1.5, 7.1.2, 8.0.7.

How severe is CVE-2021-37704?

CVE-2021-37704 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of phpfastcache/phpfastcache are affected by CVE-2021-37704?

phpfastcache/phpfastcache (composer) versions < 6.1.5 is affected.

Is there a fix for CVE-2021-37704?

Yes. CVE-2021-37704 is fixed in 6.1.5, 7.1.2, 8.0.7. Upgrade to this version or later.

Is CVE-2021-37704 exploitable, and should I be worried?

Whether CVE-2021-37704 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether CVE-2021-37704 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2021-37704?

Upgrade: phpfastcache/phpfastcache to 6.1.5 or later, phpfastcache/phpfastcache to 7.1.2 or later, phpfastcache/phpfastcache to 8.0.7 or later.

CVE-2021-37704 in phpfastcache/phpfastcache

Q: How severe is CVE-2021-37704?

CVE-2021-37704 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of phpfastcache/phpfastcache are affected by CVE-2021-37704?

phpfastcache/phpfastcache (composer) versions < 6.1.5 is affected.

Q: Is there a fix for CVE-2021-37704?

Yes. CVE-2021-37704 is fixed in 6.1.5, 7.1.2, 8.0.7. Upgrade to this version or later.

Q: Is CVE-2021-37704 exploitable, and should I be worried?

Whether CVE-2021-37704 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether CVE-2021-37704 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix CVE-2021-37704?

Upgrade: phpfastcache/phpfastcache to 6.1.5 or later, phpfastcache/phpfastcache to 7.1.2 or later, phpfastcache/phpfastcache to 8.0.7 or later.

Summary

Exposed phpinfo() leadked via documentation files

Workarounds

Protect the /vendor directory from public access.

References

The first issue revealing this vulnerability is located here: https://github.com/flextype/flextype/issues/567
V6 fix: https://github.com/PHPSocialNetwork/phpfastcache/pull/815
V7 fix: https://github.com/PHPSocialNetwork/phpfastcache/pull/814
V8 fix: https://github.com/PHPSocialNetwork/phpfastcache/pull/813

For more information

If you have any questions or comments about this advisory:

Open an issue in our issue tracker
Email us at [email protected]

Impact

The phpinfo() can be exposed if the /vendor is not protected from public access. This is a rare situation today since the vendor directory is often located outside the web directory or protected via server rule (.htaccess, etc).

CVE-2021-37704 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (6.1.5, 7.1.2, 8.0.7); upgrading removes the vulnerable code path.

Affected versions

phpfastcache/phpfastcache (< 6.1.5) phpfastcache/phpfastcache (>= 7.0.0, < 7.1.2) phpfastcache/phpfastcache (>= 8.0.0, < 8.0.7)

Security releases

phpfastcache/phpfastcache → 6.1.5 (composer) phpfastcache/phpfastcache → 7.1.2 (composer) phpfastcache/phpfastcache → 8.0.7 (composer)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Only the v6, v7 and v8 will be patched respectively in 8.0.7, 7.1.2, 6.1.5.
Older versions such as v5, v4 are not longer supported and will NOT be patched.

Frequently Asked Questions

What is CVE-2021-37704? CVE-2021-37704 is a medium-severity security vulnerability in phpfastcache/phpfastcache (composer), affecting versions < 6.1.5. It is fixed in 6.1.5, 7.1.2, 8.0.7.
How severe is CVE-2021-37704? CVE-2021-37704 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of phpfastcache/phpfastcache are affected by CVE-2021-37704? phpfastcache/phpfastcache (composer) versions < 6.1.5 is affected.
Is there a fix for CVE-2021-37704? Yes. CVE-2021-37704 is fixed in 6.1.5, 7.1.2, 8.0.7. Upgrade to this version or later.
Is CVE-2021-37704 exploitable, and should I be worried? Whether CVE-2021-37704 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether CVE-2021-37704 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix CVE-2021-37704?
- Upgrade phpfastcache/phpfastcache to 6.1.5 or later
- Upgrade phpfastcache/phpfastcache to 7.1.2 or later
- Upgrade phpfastcache/phpfastcache to 8.0.7 or later

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