QID 239649

Date Published: 2021-09-23

QID 239649: Red Hat Update for krb5 (RHSA-2021:3576)

Kerberos is a network authentication system, which can improve the security of your network by eliminating the insecure practice of sending passwords over the network in unencrypted form. It allows clients and servers to authenticate to each other with the help of a trusted third party, the Kerberos key distribution center (KDC).

Security Fix(es): krb5: Sending a request containing PA-ENCRYPTED-CHALLENGE padata element without using FAST could result in NULL dereference in KDC which leads to DoS (CVE-2021-36222) krb5: NULL pointer dereference in process_tgs_req()
in kdc/do_tgs_req.c via a FAST inner body that lacks server field (CVE-2021-37750)

Affected Products:

Red Hat Enterprise Linux for x86_64 8 x86_64
Red Hat Enterprise Linux for x86_64 - Extended Update Support 8.4 x86_64
Red Hat Enterprise Linux Server - AUS 8.4 x86_64
Red Hat Enterprise Linux for IBM z Systems 8 s390x
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 8.4 s390x
Red Hat Enterprise Linux for Power, little endian 8 ppc64le
Red Hat Enterprise Linux for Power, little endian - Extended Update Support 8.4 ppc64le
Red Hat Enterprise Linux Server - TUS 8.4 x86_64
Red Hat Enterprise Linux for ARM 64 8 aarch64
Red Hat Enterprise Linux for ARM 64 - Extended Update Support 8.4 aarch64
Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 8.4 ppc64le
Red Hat Enterprise Linux Server - Update Services for SAP Solutions 8.4 x86_64

Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

On successful exploitation, it could allow an attacker to execute code.

  • CVSS V3 rated as High - 7.5 severity.
  • CVSS V2 rated as Medium - 5 severity.
    • Solution
    Upgrade to the latest packages which contain a patch. Refer to Applying Package Updates to RHEL system for details.

    Refer to Red Hat security advisory RHSA-2021:3576 to address this issue and obtain more information.

    Vendor References

    CVEs related to QID 239649

    CVE-2021-36222 | CVE-2021-37750 |
    Software Advisories
    Advisory ID Software Component Link
    RHSA-2021:3576 Red Hat Enterprise Linux URL Logo access.redhat.com/errata/RHSA-2021:3576?language=en
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