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GHSA-2p68-f74v-9wc6

CriticalCVSS 9.8 / 10
Published May 26, 2020·Last modified May 9, 2025
Affected Components(0)

No affected components available

Description

In ActiveSupport, there is potentially unexpected behaviour in the MemCacheStore and RedisCacheStore where, when untrusted user input is written to the cache store using the raw: true parameter, re-reading the result from the cache can evaluate the user input as a Marshalled object instead of plain text. Vulnerable code looks like:

data = cache.fetch("demo", raw: true) { untrusted_string }

Versions Affected: rails < 5.2.5, rails < 6.0.4 Not affected: Applications not using MemCacheStore or RedisCacheStore. Applications that do not use the raw option when storing untrusted user input. Fixed Versions: rails >= 5.2.4.3, rails >= 6.0.3.1

Impact

Unmarshalling of untrusted user input can have impact up to and including RCE. At a minimum, this vulnerability allows an attacker to inject untrusted Ruby objects into a web application. In addition to upgrading to the latest versions of Rails, developers should ensure that whenever they are calling Rails.cache.fetch they are using consistent values of the raw parameter for both reading and writing, especially in the case of the RedisCacheStore which does not, prior to these changes, detect if data was serialized using the raw option upon deserialization.

Workarounds

It is recommended that application developers apply the suggested patch or upgrade to the latest release as soon as possible. If this is not possible, we recommend ensuring that all user-provided strings cached using the raw argument should be double-checked to ensure that they conform to the expected format.

Risk Scores
Base Score
9.8

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
9.0

Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.

EPSS
45.73%

The exploit probability is high. The vulnerability is very likely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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