CVE-2023-41338

Fiber is an Express inspired web framework built in the go language. Versions of gofiber prior to 2.49.2 did not properly restrict access to localhost. This issue impacts users of our project who rely on the ctx.IsFromLocal method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost. Setting X-Forwarded-For: 127.0.0.1 in a request from a foreign host, will result in true for ctx.IsFromLocal. Access is limited to the scope of the affected process. This issue has been patched in version 2.49.2 with commit b8c9ede6. Users are advised to upgrade. There are no known workarounds to remediate this vulnerability without upgrading to the patched version.

Fiber is an Express inspired web framework built in the go language. Versions of gofiber prior to 2.49.2 did not properly restrict access to localhost. This issue impacts users of our project who rely on the ctx.IsFromLocal method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost. Setting X-Forwarded-For: 127.0.0.1 in a request from a foreign host, will result in true for ctx.IsFromLocal. Access is limited to the scope of the affected process. This issue has been patched in version 2.49.2 with commit b8c9ede6. Users are advised to upgrade. There are no known workarounds to remediate this vulnerability without upgrading to the patched version.

Impact

This vulnerability can be categorized as a security misconfiguration. It impacts users of our project who rely on the ctx.IsFromLocal() method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost.

In it's implementation it uses c.IPs():

// IPs returns a string slice of IP addresses specified in the X-Forwarded-For request header.
// When IP validation is enabled, only valid IPs are returned.
func (c *Ctx) IPs() []string {
    return c.extractIPsFromHeader(HeaderXForwardedFor)
}

Thereby, setting X-Forwarded-For: 127.0.0.1 in a request from a foreign host, will result in true for ctx.IsFromLocal()

Patches

This issue has been patched in v2.49.2 with commit b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc

Workarounds

Currently, there are no known workarounds to remediate this vulnerability without upgrading to the patched version. We strongly advise users to apply the patch as soon as it is released.

References

For further information and context regarding this security issue, please refer to the following resources:

• Mozilla Developer Network - X-Forwarded-For

Fiber is an Express inspired web framework built in the go language. Versions of gofiber prior to 2.49.2 did not properly restrict access to localhost. This issue impacts users of our project who rely on the ctx.IsFromLocal method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost. Setting X-Forwarded-For: 127.0.0.1 in a request from a foreign host, will result in true for ctx.IsFromLocal. Access is limited to the scope of the affected process. This issue has been patched in version 2.49.2 with commit b8c9ede6. Users are advised to upgrade. There are no known workarounds to remediate this vulnerability without upgrading to the patched version.

Fiber is an Express inspired web framework built in the go language. Versions of gofiber prior to 2.49.2 did not properly restrict access to localhost. This issue impacts users of our project who rely on the ctx.IsFromLocal method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost. Setting X-Forwarded-For: 127.0.0.1 in a request from a foreign host, will result in true for ctx.IsFromLocal. Access is limited to the scope of the affected process. This issue has been patched in version 2.49.2 with commit b8c9ede6. Users are advised to upgrade. There are no known workarounds to remediate this vulnerability without upgrading to the patched version.

Impact

This vulnerability can be categorized as a security misconfiguration. It impacts users of our project who rely on the ctx.IsFromLocal() method to restrict access to localhost requests. If exploited, it could allow unauthorized access to resources intended only for localhost.

In it's implementation it uses c.IPs():

// IPs returns a string slice of IP addresses specified in the X-Forwarded-For request header.
// When IP validation is enabled, only valid IPs are returned.
func (c *Ctx) IPs() []string {
    return c.extractIPsFromHeader(HeaderXForwardedFor)
}

Thereby, setting X-Forwarded-For: 127.0.0.1 in a request from a foreign host, will result in true for ctx.IsFromLocal()

Patches

This issue has been patched in v2.49.2 with commit b8c9ede6efa231116c4bd8bb9d5e03eac1cb76dc

Workarounds

Currently, there are no known workarounds to remediate this vulnerability without upgrading to the patched version. We strongly advise users to apply the patch as soon as it is released.

References

For further information and context regarding this security issue, please refer to the following resources:

• Mozilla Developer Network - X-Forwarded-For

The Ctx.IsFromLocal function can incorrectly report a request as being sent from localhost when the request contains an X-Forwarded-For header containing a localhost IP address.