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ubuntucveUbuntu.comUB:CVE-2021-3711
HistoryAug 24, 2021 - 12:00 a.m.

CVE-2021-3711

2021-08-2400:00:00
ubuntu.com
ubuntu.com
39

9.8 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

7.5 High

CVSS2

Access Vector

Access Complexity

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:P/I:P/A:P

0.068 Low

EPSS

Percentile

93.9%

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).

OSVersionArchitecturePackageVersionFilename
ubuntu18.04noarchopenssl< 1.1.1-1ubuntu2.1~18.04.13UNKNOWN
ubuntu20.04noarchopenssl< 1.1.1f-1ubuntu2.8UNKNOWN
ubuntu21.04noarchopenssl< 1.1.1j-1ubuntu3.5UNKNOWN
ubuntu21.10noarchopenssl< 1.1.1l-1ubuntu1UNKNOWN
ubuntu22.04noarchopenssl< 1.1.1l-1ubuntu1UNKNOWN
ubuntu22.10noarchopenssl< 1.1.1l-1ubuntu1UNKNOWN
ubuntu23.04noarchopenssl< 1.1.1l-1ubuntu1UNKNOWN
ubuntu23.10noarchopenssl< 1.1.1l-1ubuntu1UNKNOWN
ubuntu24.04noarchopenssl< 1.1.1l-1ubuntu1UNKNOWN

9.8 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

7.5 High

CVSS2

Access Vector

Access Complexity

Authentication

NONE

Confidentiality Impact

PARTIAL

Integrity Impact

PARTIAL

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:P/I:P/A:P

0.068 Low

EPSS

Percentile

93.9%