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Debian LTS Advisory DLA-2647-1                [email protected]
https://www.debian.org/lts/security/               Emilio Pozuelo Monfort
May 04, 2021                                  https://wiki.debian.org/LTS
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Package        : bind9
Version        : 1:9.10.3.dfsg.P4-12.3+deb9u9
CVE ID         : CVE-2021-25214 CVE-2021-25215 CVE-2021-25216
Debian Bug     : 987741 987742 987743

Several vulnerabilities were discovered in BIND, a DNS server


    Greg Kuechle discovered that a malformed incoming IXFR transfer
    could trigger an assertion failure in named, resulting in denial
    of service.


    Siva Kakarla discovered that named could crash when a DNAME record
    placed in the ANSWER section during DNAME chasing turned out to be
    the final answer to a client query.


    It was discovered that the SPNEGO implementation used by BIND is
    prone to a buffer overflow vulnerability. This update switches to
    use the SPNEGO implementation from the Kerberos libraries.

For Debian 9 stretch, these problems have been fixed in version

We recommend that you upgrade your bind9 packages.

For the detailed security status of bind9 please refer to
its security tracker page at:

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