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Fencer Vulns
high 7.5

CVE-2023-6516 json

Specific recursive query patterns may lead to an out-of-memory condition

published 2024-02-13 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-58747

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits
0
none known

Summary

To keep its cache database efficient, `named` running as a recursive resolver occasionally attempts to clean up the database. It uses several methods, including some that are asynchronous: a small chunk of memory pointing to the cache element that can be cleaned up is first allocated and then queued for later processing. It was discovered that if the resolver is continuously processing query patterns triggering this type of cache-database maintenance, `named` may not be able to handle the cleanup events in a timely manner. This in turn enables the list of queued cleanup events to grow infinitely large over time, allowing the configured `max-cache-size` limit to be significantly exceeded. This issue affects BIND 9 versions 9.16.0 through 9.16.45 and 9.16.8-S1 through 9.16.45-S1.

Patch / fix

  • isc bind 9.16.48, 9.16.48-S1
  • bind9 Debian 14, Debian 13, Debian 12 1:9.17.19-1

debian advisories DEBIAN-CVE-2023-6516

  • bind9 Ubuntu 20.04 LTS 1:9.16.48-0ubuntu0.20.04.1

ubuntu advisories UBUNTU-CVE-2023-6516

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 RHEL 9 32:9.16.23-18.el9_4.1
  • bind-libs RHEL 9 32:9.16.23-18.el9_4.1
  • bind-utils RHEL 9 32:9.16.23-18.el9_4.1
  • bind-chroot RHEL 9 32:9.16.23-18.el9_4.1
  • bind-license RHEL 9 32:9.16.23-18.el9_4.1
  • python3-bind RHEL 9 32:9.16.23-18.el9_4.1
  • bind-dyndb-ldap RHEL 9 11.9-9.el9_4
  • bind-dnssec-utils RHEL 9 32:9.16.23-18.el9_4.1

red hat advisories RHSA-2024:2551RHSA-2024:1800RHSA-2024:1803RHSA-2024:1789RHSA-2024:1781RHSA-2024:1647

  • bind SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +1 more 9.16.6-150000.12.74.2
  • libuv SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS +1 more 1.18.0-150000.3.2.1
  • bind SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Module for Basesystem 15 SP6 +2 more 9.16.6-150300.22.44.1
  • bind SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +3 more 9.16.48-150400.5.40.1
  • bind SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 9.16.48-150500.8.16.1

suse advisories SUSE-SU-2024:2033-1SUSE-SU-2024:1982-1SUSE-SU-2024:0590-1SUSE-SU-2024:0574-1

  • bind openSUSE Tumbleweed 9.18.24-1.1

opensuse advisories openSUSE-SU-2024:13687-1

  • bind AlmaLinux 9 32:9.16.23-18.el9_4.1
  • bind-libs AlmaLinux 9 32:9.16.23-18.el9_4.1
  • bind-utils AlmaLinux 9 32:9.16.23-18.el9_4.1
  • bind-chroot AlmaLinux 9 32:9.16.23-18.el9_4.1
  • bind-license AlmaLinux 9 32:9.16.23-18.el9_4.1
  • python3-bind AlmaLinux 9 32:9.16.23-18.el9_4.1
  • bind-dyndb-ldap AlmaLinux 9 11.9-9.el9_4.alma.1
  • bind-dnssec-utils AlmaLinux 9 32:9.16.23-18.el9_4.1

almalinux advisories ALSA-2024:2551ALSA-2024:1781ALSA-2024:1789

  • bind Rocky Linux 9 2:9.16.23-18.el9_4.1
  • bind-dyndb-ldap Rocky Linux 9 11.9-9.el9_4
  • bind9.16 Rocky Linux 8 2:9.16.23-0.16.el8_9.2

rocky linux advisories RLSA-2024:2551RLSA-2024:1781

  • bind Alpine 3.16 9.16.48-r0
  • bind Alpine 3.24, Alpine 3.23, Alpine 3.22 +5 more 9.18.24-r0

alpine advisories ALPINE-CVE-2023-6516

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

  • bind Azure Linux 3.0 9.19.21-1

azure linux advisories AZL-34561

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2023-6516 updated cvss 7.5

bind9: Specific recursive query patterns may lead to an out-of-memory condition

  • Red Hat CodeReady Linux Builder (v. 8) bind9.16-libs 9.16.23-0.16.el8_9.2
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1781
  • Red Hat CodeReady Linux Builder (v. 9) bind-libs 9.16.23-14.el9_3.4
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1789
  • Red Hat CodeReady Linux Builder EUS (v.8.6) bind9.16-libs 9.16.23-0.7.el8_6.5, python3-bind9.16 9.16.23-0.7.el8_6.5, bind9.16-dnssec-utils 9.16.23-0.7.el8_6.5
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1647
  • Red Hat CodeReady Linux Builder EUS (v.8.8) bind9.16-libs 9.16.23-0.14.el8_8.4
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1648
  • Red Hat CodeReady Linux Builder EUS (v.9.0) bind-libs 9.16.23-1.el9_0.5
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1800
  • Red Hat CodeReady Linux Builder EUS (v.9.2) bind-libs 9.16.23-11.el9_2.4
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1803
  • Red Hat Enterprise Linux AppStream (v. 8) bind9.16 9.16.23-0.16.el8_9.2, bind9.16-libs 9.16.23-0.16.el8_9.2, bind9.16-utils 9.16.23-0.16.el8_9.2, bind9.16-chroot 9.16.23-0.16.el8_9.2, bind9.16-license 9.16.23-0.16.el8_9.2, python3-bind9.16 9.16.23-0.16.el8_9.2, +1 more
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1781
  • Red Hat Enterprise Linux AppStream (v. 9) bind 9.16.23-14.el9_3.4, bind 9.16.23-18.el9_4.1, bind-dyndb-ldap 11.9-9.el9_4, bind-libs 9.16.23-14.el9_3.4, bind-libs 9.16.23-18.el9_4.1, bind-utils 9.16.23-14.el9_3.4, +10 more
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1789
show 6 more
  • Red Hat Enterprise Linux AppStream EUS (v.8.6) bind9.16 9.16.23-0.7.el8_6.5, bind9.16-libs 9.16.23-0.7.el8_6.5, bind9.16-utils 9.16.23-0.7.el8_6.5, bind9.16-chroot 9.16.23-0.7.el8_6.5, bind9.16-license 9.16.23-0.7.el8_6.5
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1647
  • Red Hat Enterprise Linux AppStream EUS (v.8.8) bind9.16 9.16.23-0.14.el8_8.4, bind9.16-libs 9.16.23-0.14.el8_8.4, bind9.16-utils 9.16.23-0.14.el8_8.4, bind9.16-chroot 9.16.23-0.14.el8_8.4, bind9.16-license 9.16.23-0.14.el8_8.4, python3-bind9.16 9.16.23-0.14.el8_8.4, +1 more
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1648
  • Red Hat Enterprise Linux AppStream EUS (v.9.0) bind 9.16.23-1.el9_0.5, bind-libs 9.16.23-1.el9_0.5, bind-utils 9.16.23-1.el9_0.5, bind-chroot 9.16.23-1.el9_0.5, bind-dyndb-ldap 11.9-7.el9_0.1, bind-license 9.16.23-1.el9_0.5, +2 more
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1800
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) bind 9.16.23-11.el9_2.4, bind-libs 9.16.23-11.el9_2.4, bind-utils 9.16.23-11.el9_2.4, bind-chroot 9.16.23-11.el9_2.4, bind-dyndb-ldap 11.9-8.el9_2.2, bind-license 9.16.23-11.el9_2.4, +2 more
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:1803
  • Red Hat Enterprise Linux CRB (v. 9) bind-libs 9.16.23-18.el9_4.1
    fixed: vendor fix “There is no available mitigation for this issue other than applying the required fixes via the released updates.” RHSA-2024:2551
  • 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 Red Hat Enterprise Linux 9 dhcp, dhcp-relay, dhcp-client, dhcp-common, dhcp-server
    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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.10% chance of exploitation in the next 30 days, higher than 65% 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

Affected products

  • ISC BIND 9
  • isc bind

Classification

Weakness
  • CWE-789 Memory Allocation with Excessive Size Value
  • CWE-770 Allocation of Resources Without Limits or Throttling

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.