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Debian Security Advisory DSA-4689-1                   security@debian.org
https://www.debian.org/security/                     Salvatore Bonaccorso
May 19, 2020                          https://www.debian.org/security/faq
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Package        : bind9
CVE ID         : CVE-2019-6477 CVE-2020-8616 CVE-2020-8617
Debian Bug     : 945171

Several vulnerabilities were discovered in BIND, a DNS server
implementation.

CVE-2019-6477

    It was discovered that TCP-pipelined queries can bypass tcp-client
    limits resulting in denial of service.

CVE-2020-8616

    It was discovered that BIND does not sufficiently limit the number
    of fetches performed when processing referrals. An attacker can take
    advantage of this flaw to cause a denial of service (performance
    degradation) or use the recursing server in a reflection attack with
    a high amplification factor.

CVE-2020-8617

    It was discovered that a logic error in the code which checks TSIG
    validity can be used to trigger an assertion failure, resulting in
    denial of service.

For the oldstable distribution (stretch), these problems have been fixed
in version 1:9.10.3.dfsg.P4-12.3+deb9u6.

For the stable distribution (buster), these problems have been fixed in
version 1:9.11.5.P4+dfsg-5.1+deb10u1.

We recommend that you upgrade your bind9 packages.

For the detailed security status of bind9 please refer to its security
tracker page at:
https://security-tracker.debian.org/tracker/source-package/bind9

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/

Mailing list: debian-security-announce@lists.debian.org