A heimdal security update has been released for Debian GNU/Linux 11 to address several vulnerabilities.

DSA 5287-1: heimdal security update

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Debian Security Advisory DSA-5287-1 security@debian.org
  https://www.debian.org/security/ Salvatore Bonaccorso
November 22, 2022   https://www.debian.org/security/faq
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Package : heimdal
CVE ID : CVE-2021-3671 CVE-2021-44758 CVE-2022-3437 CVE-2022-41916
CVE-2022-42898 CVE-2022-44640
Debian Bug : 996586

Several vulnerabilities were discovered in Heimdal, an implementation of
Kerberos 5 that aims to be compatible with MIT Kerberos.

CVE-2021-3671

Joseph Sutton discovered that the Heimdal KDC does not validate that
the server name in the TGS-REQ is present before dereferencing,
which may result in denial of service.

CVE-2021-44758

It was discovered that Heimdal is prone to a NULL dereference in
acceptors where an initial SPNEGO token that has no acceptable
mechanisms, which may result in denial of service for a server
application that uses SPNEGO.

CVE-2022-3437

Several buffer overflow flaws and non-constant time leaks were
discovered when using 1DES, 3DES or RC4 (arcfour).

CVE-2022-41916

An out-of-bounds memory access was discovered when Heimdal
normalizes Unicode, which may result in denial of service.

CVE-2022-42898

It was discovered that integer overflows in PAC parsing may result
in denial of service for Heimdal KDCs or possibly Heimdal servers.

CVE-2022-44640

It was discovered that the Heimdal's ASN.1 compiler generates code
that allows specially crafted DER encodings to invoke an invalid
free on the decoded structure upon decode error, which may result in
remote code execution in the Heimdal KDC.

For the stable distribution (bullseye), these problems have been fixed in
version 7.7.0+dfsg-2+deb11u2.

We recommend that you upgrade your heimdal packages.

For the detailed security status of heimdal please refer to its security
tracker page at:
  https://security-tracker.debian.org/tracker/heimdal

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at:   https://www.debian.org/security/