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Fencer Vulns
high 7.5

CVE-2020-8620 json

In BIND 9.15.6 -> 9.16.5, 9.17.0 -> 9.17.3, An attacker who can establish a TCP connection with the server and send data on that connection…

published 2020-08-21 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-29468

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.9%
EPSS 3.9% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

In BIND 9.15.6 -> 9.16.5, 9.17.0 -> 9.17.3, An attacker who can establish a TCP connection with the server and send data on that connection can exploit this to trigger the assertion failure, causing the server to exit.

Patch / fix

  • ISC BIND9 9.16.6, 9.17.4
  • bind9 Debian 14, Debian 13, Debian 12 1:9.16.6-1

debian advisories DEBIAN-CVE-2020-8620

  • bind9 Ubuntu 20.04 LTS 1:9.16.1-0ubuntu2.3

ubuntu advisories UBUNTU-CVE-2020-8620

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • bind SLES for SAP 15, SLES 15-LTSS, SLE Module for Server Applications 15 SP2 +5 more 9.16.6-12.32.1
  • sysuser-tools SLES for SAP 15, SLES 15-LTSS, SLE Module for Development Tools 15 SP2 +4 more 2.0-4.2.8

suse advisories SUSE-SU-2020:2914-1

  • bind openSUSE Tumbleweed 9.16.20-1.4
  • bind openSUSE Leap 15.1 9.16.6-lp151.11.9.1
  • libuv openSUSE Leap 15.1 1.18.0-lp151.3.3.1
  • sysuser-tools openSUSE Leap 15.1 2.0-lp151.4.3.1
  • bind openSUSE Leap 15.2 9.16.6-lp152.14.3.1
  • libuv openSUSE Leap 15.2 1.18.0-lp152.4.3.1
  • sysuser-tools openSUSE Leap 15.2 2.0-lp152.5.3.1

opensuse advisories openSUSE-SU-2024:10650-1openSUSE-SU-2020:1701-1openSUSE-SU-2020:1699-1

  • bind Alpine 3.24, Alpine 3.23, Alpine 3.22 +12 more 9.16.6-r0

alpine advisories ALPINE-CVE-2020-8620

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-8620 updated cvss 7.5

bind: A specially crafted large TCP payload can trigger an assertion failure in tcpdns.c

  • Red Hat Enterprise Linux 5 bind, bind97 Red Hat Enterprise Linux 6 bind, bind-sdb, bind-libs, bind-utils, bind-chroot Red Hat Enterprise Linux 7 bind, bind-sdb, bind-libs, bind-utils, bind-chroot, bind-pkcs11, +6 more Red Hat Enterprise Linux 8 bind, bind-sdb, bind-libs, bind-utils, bind-chroot, bind-pkcs11, +7 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.90% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • ISC BIND9

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.