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🛡️ CVE-2023-4236 — bind

🟠 CVSS 7.5 — High ✅ No Known Exploit CWE-617 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

A flaw in the networking code handling DNS-over-TLS queries may cause named to terminate unexpectedly due to an assertion failure. This happens when internal data structures are incorrectly reused under significant DNS-over-TLS query load.

This issue affects BIND 9 versions 9.18.0 through 9.18.18 and 9.18.11-S1 through 9.18.18-S1.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

CVE-2023-4236 is classified as CWE-617: Reachable Assertion. The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

Affected software

CVE-2023-4236 is recorded against 8 packages.

  • bind
  • debian-linux
  • fedora
  • h300s-firmware
  • h410c-firmware
  • h410s-firmware
  • h500s-firmware
  • h700s-firmware

Timeline and source

Published on 20 September 2023 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

www.openwall.com
kb.isc.org
lists.fedoraproject.org
lists.fedoraproject.org
lists.fedoraproject.org
security.netapp.com
www.debian.org
www.openwall.com
kb.isc.org
lists.fedoraproject.org
lists.fedoraproject.org
lists.fedoraproject.org
security.netapp.com
www.debian.org

Other advisories for this package

bind has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-617: Reachable Assertion) in other software:

CVE-2023-4236 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-617
Public Exploit ✅ No
Source NVD
Published 2023-09-20
Updated 2026-08-20
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
bind
debian-linux
fedora
h300s-firmware
h410c-firmware
h410s-firmware
h500s-firmware
h700s-firmware

References

Mailing List, Third Party Advisory http://www.openwall.com/lists/oss-security/2023/09/20/2
Mailing List, Third Party Advisory http://www.openwall.com/lists/oss-security/2023/09/20/2

Site Security Check

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CVE-2023-4236 is rated CVSS 7.5 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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