Is CVE-2021-3711 being actively exploited?

It is not currently in CISA's KEV catalog. Its EPSS exploitation probability is 88%.

What products does CVE-2021-3711 affect?

Tracked products affected include OpenSSL, PeopleSoft Enterprise PeopleTools. Check the version you run to see whether it is affected.

How do I fix CVE-2021-3711?

Apply the vendor fix promptly. Upgrade affected products to a fixed version.

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CVE-2021-3711

Q: What is CVE-2021-3711?

CVE-2021-3711 is a critical-severity software vulnerability (Buffer overflow) with a CVSS score of 9.8. In order to decrypt SM2 encrypted data an application is expected to call the API function EVP_PKEY_decrypt(). Typically an application will call this function twice. The first time, on entry, the "out" parameter can be NULL and, on exit, t

CRITICAL severity · CVSS 9.8 · Buffer overflow

9.8CVSS CRITICAL

Summary

In order to decrypt SM2 encrypted data an application is expected to call the API function EVP_PKEY_decrypt(). Typically an application will call this function twice. The first time, on entry, the "out" parameter can be NULL and, on exit, the "outlen" parameter is populated with the buffer size required to hold the decrypted plaintext. The application can then allocate a sufficiently sized buffer and call EVP_PKEY_decrypt() again, but this time passing a non-NULL value for the "out" parameter. A bug in the implementation of the SM2 decryption code means that the calculation of the buffer size required to hold the plaintext returned by the first call to EVP_PKEY_decrypt() can be smaller than the actual size required by the second call. This can lead to a buffer overflow when EVP_PKEY_decrypt() is called by the application a second time with a buffer that is too small. A malicious attacker who is able present SM2 content for decryption to an application could cause attacker chosen data to overflow the buffer by up to a maximum of 62 bytes altering the contents of other data held after the buffer, possibly changing application behaviour or causing the application to crash. The location of the buffer is application dependent but is typically heap allocated. Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k).

Impact & exploitability

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

Confidentiality impactHigh

Integrity impactHigh

Availability impactHigh

Exploit probability (EPSS)88%

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

Affected products we track (2)

OpenSSL PeopleSoft Enterprise PeopleTools

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.

CVE-2021-3711

Summary

Impact & exploitability

Affected products we track (2)

Recommendation

Additional information