CVE-2021-23841

Publication date 16 February 2021

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

5.9 · Medium

Score breakdown

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).

Read the notes from the security team

Status

Package Ubuntu Release Status
edk2 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty Not in release
nodejs 20.10 groovy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected
openssl 20.10 groovy
Fixed 1.1.1f-1ubuntu4.2
20.04 LTS focal
Fixed 1.1.1f-1ubuntu2.2
18.04 LTS bionic
Fixed 1.1.1-1ubuntu2.1~18.04.8
16.04 LTS xenial
Fixed 1.0.2g-1ubuntu4.19
14.04 LTS trusty
openssl1.0 20.10 groovy Not in release
20.04 LTS focal Not in release
18.04 LTS bionic
Fixed 1.0.2n-1ubuntu5.6
16.04 LTS xenial Not in release
14.04 LTS trusty Not in release

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Notes

mdeslaur

edk2 doesn't use the affected function

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
openssl

Severity score breakdown

Parameter Value
Base score 5.9 · Medium
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-4738-1
    • OpenSSL vulnerabilities
    • 18 February 2021
    • USN-4745-1
    • OpenSSL vulnerabilities
    • 23 February 2021

Other references