dbcve.org
FedoraOperating system · Fedoraproject

CVE-2023-5517

HIGH · 7.5 CVSS v3.1 Published 2024-02-13
Fix available
A fix is available. Upgrade to after 9.19.19 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw in query-handling code can cause `named` to exit prematurely with an assertion failure when: - `nxdomain-redirect <domain>;` is configured, and - the resolver receives a PTR query for an RFC 1918 address that would normally result in an authoritative NXDOMAIN response. This issue affects BIND 9 versions 9.12.0 through 9.16.45, 9.18.0 through 9.18.21, 9.19.0 through 9.19.19, 9.16.8-S1 through 9.16.45-S1, and 9.18.11-S1 through 9.18.21-S1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A flaw in BIND 9's query handling causes an assertion failure leading to denial of service. When `nxdomain-redirect` is configured and the resolver receives a PTR query for an RFC 1918 address that would normally return an authoritative NXDOMAIN, the named process exits prematurely.

MitigationUpdate BIND 9 to version 9.16.46, 9.18.22, 9.19.20, or later. If immediate patching is not possible, consider removing or disabling the `nxdomain-redirect` configuration directive until the update can be applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FedoraOperating system
Affected:= 38= 39
Active Iq Unified ManagerApplication
Affected:all versions
BindApplication
Affected:>= 9.12.0, <= 9.16.45>= 9.18.0, <= 9.18.21>= 9.19.0, <= 9.19.19= 9.16.8= 9.16.11= 9.16.12= 9.16.13= 9.16.14= 9.16.21= 9.16.32= 9.16.36= 9.16.43

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed BIND version
    Run `named -v` or `bind -v` to determine the version of BIND 9 installed
    Affected if The installed version falls within one of the affected ranges: 9.12.0-9.16.45, 9.18.0-9.18.21, 9.19.0-9.19.19, or specific versions 9.16.8, 9.16.11-9.16.14, 9.16.21, 9.16.32, 9.16.36, 9.16.43
  2. Locate BIND configuration file
    Identify the named.conf file location, typically in /etc/named.conf, /etc/bind/named.conf, or as specified in `named -h`
    Affected if A configuration file exists and is in use by the named daemon
  3. Verify nxdomain-redirect is enabled
    Search the named.conf file (and included files) for the `nxdomain-redirect` directive using `grep -r "nxdomain-redirect" /etc/named.conf` or manual inspection
    Affected if The directive `nxdomain-redirect` is present and set to any value (enabled)
  4. Confirm PTR query handling for RFC 1918 space
    Check if the server is configured for recursion (allow-recursion or recursion yes;) OR if it serves as authoritative for RFC 1918 reverse zones (10.in-addr.arpa, 16.172.in-addr.arpa through 31.172.in-addr.arpa, 168.192.in-addr.arpa)
    Affected if The server handles PTR queries for any RFC 1918 private address ranges either through recursion or authoritative zone delegation

The environment is affected if BIND 9 version is within the vulnerable range AND nxdomain-redirect is configured AND the server processes PTR queries for RFC 1918 addresses.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 9.19.19
Interim mitigation

Update BIND 9 to version 9.16.46, 9.18.22, 9.19.20, or later. If immediate patching is not possible, consider removing or disabling the `nxdomain-redirect` configuration directive until the update can be applied.

Recommended fix Moderate confidence

BIND 9.18.22+ or 9.19.20+ or 9.16.46+ (or Fedora patched packages)

  1. 1. Identify the currently installed BIND version using: `named -v` or `rpm -q bind`
  2. 2. If using Fedora 38 or 39, run: `sudo dnf update bind` to obtain the patched package
  3. 3. For other distributions, upgrade to BIND version 9.18.22 or later (for 9.18.x line), 9.19.20 or later (for 9.19.x line), or 9.16.46 or later (for 9.16.x line)
  4. 4. After upgrading, restart the named service: `sudo systemctl restart named`
  5. 5. Verify the service is running without assertion failures: `sudo systemctl status named`
  6. 6. If nxdomain-redirect is configured, verify the configuration is working correctly with: `dig @localhost <PTR-record-for-RFC1918-address>`
Caveat Upgrading BIND may introduce subtle configuration or behavior changes; review release notes before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fedora Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-5517 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-5517 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data