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ubuntucveUbuntu.comUB:CVE-2021-23841
HistoryFeb 16, 2021 - 12:00 a.m.

CVE-2021-23841

2021-02-1600:00:00
ubuntu.com
ubuntu.com
22

5.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

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

4.3 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

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

0.004 Low

EPSS

Percentile

73.6%

The OpenSSL public API function X509_issuer_and_serial_hash() attempts to
create a unique hash value based on the issuer and serial number data
contained within an X509 certificate. However it fails to correctly handle
any errors that may occur while parsing the issuer field (which might occur
if the issuer field is maliciously constructed). This may subsequently
result in a NULL pointer deref and a crash leading to a potential denial of
service attack. The function X509_issuer_and_serial_hash() is never
directly called by OpenSSL itself so applications are only vulnerable if
they use this function directly and they use it on certificates that may
have been obtained from untrusted sources. OpenSSL versions 1.1.1i and
below are affected by this issue. Users of these versions should upgrade to
OpenSSL 1.1.1j. OpenSSL versions 1.0.2x and below are affected by this
issue. However OpenSSL 1.0.2 is out of support and no longer receiving
public updates. Premium support customers of OpenSSL 1.0.2 should upgrade
to 1.0.2y. Other users should upgrade to 1.1.1j. Fixed in OpenSSL 1.1.1j
(Affected 1.1.1-1.1.1i). Fixed in OpenSSL 1.0.2y (Affected 1.0.2-1.0.2x).

Notes

Author Note
mdeslaur edk2 doesn’t use the affected function
OSVersionArchitecturePackageVersionFilename
ubuntu14.04noarchopenssl< 1.0.1f-1ubuntu2.27+esm2) Available with Ubuntu Pro or Ubuntu Pro (Infra-onlyUNKNOWN
ubuntu18.04noarchopenssl< 1.1.1-1ubuntu2.1~18.04.8UNKNOWN
ubuntu20.04noarchopenssl< 1.1.1f-1ubuntu2.2UNKNOWN
ubuntu20.10noarchopenssl< 1.1.1f-1ubuntu4.2UNKNOWN
ubuntu16.04noarchopenssl< 1.0.2g-1ubuntu4.19UNKNOWN
ubuntu18.04noarchopenssl1.0< 1.0.2n-1ubuntu5.6UNKNOWN

5.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

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

4.3 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

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

0.004 Low

EPSS

Percentile

73.6%

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