Exceeding the recursive-clients quota may cause named to terminate unexpectedly when stale-answer-client-timeout is set to 0
Summary
| CVE | CVE-2023-2911 |
|---|---|
| State | PUBLISHED |
| Assigner | isc |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2023-06-21 17:15:47 UTC |
| Updated | 2026-10-24 19:10:00 UTC |
| Description | If the `recursive-clients` quota is reached on a BIND 9 resolver configured with both `stale-answer-enable yes;` and `stale-answer-client-timeout 0;`, a sequence of serve-stale-related lookups could cause `named` to loop and terminate unexpectedly due to a stack overflow. This issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Problem Types: CWE-787
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | DECLARED | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Operating System | Debian | Debian Linux | 11.0 | All | All | All |
| Operating System | Debian | Debian Linux | 12.0 | All | All | All |
| Operating System | Fedoraproject | Fedora | 37 | All | All | All |
| Operating System | Fedoraproject | Fedora | 38 | All | All | All |
| Application | Isc | Bind | All | All | All | All |
| Application | Isc | Bind | All | All | All | All |
| Application | Isc | Bind | All | All | All | All |
| Application | Isc | Bind | All | All | All | All |
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| CVE-2023-2911 | af854a3a-2127-422b-91ae-364da2661108 | kb.isc.org | Vendor Advisory |
| [SECURITY] Fedora 37 Update: bind-dyndb-ldap-11.10-15.fc37 - package-announce - Fedora Mailing-Lists | af854a3a-2127-422b-91ae-364da2661108 | lists.fedoraproject.org | Mailing List, Third Party Advisory |
| [SECURITY] Fedora 38 Update: bind-dyndb-ldap-11.10-17.fc38 - package-announce - Fedora Mailing-Lists | af854a3a-2127-422b-91ae-364da2661108 | lists.fedoraproject.org | Mailing List, Third Party Advisory |
| Debian -- Security Information -- DSA-5439-1 bind9 | af854a3a-2127-422b-91ae-364da2661108 | www.debian.org | Third Party Advisory |
| oss-security - ISC has disclosed two vulnerabilities in BIND 9 (CVE-2023-2828, CVE-2023-2911) | af854a3a-2127-422b-91ae-364da2661108 | www.openwall.com | Mailing List, Patch, Third Party Advisory |
| 403 Forbidden | af854a3a-2127-422b-91ae-364da2661108 | security.netapp.com | Third Party Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Additional Advisory Data
Solutions
CNA: Upgrade to the patched release most closely related to your current version of BIND 9: 9.16.42, 9.18.16, 9.16.42-S1, or 9.18.16-S1.
Workarounds
CNA: Setting `stale-answer-client-timeout` to `off` or to a non-zero value prevents the issue. Users of versions 9.18.10, 9.16.36, 9.16.36-S1 or older who are unable to upgrade should set `stale-answer-client-timeout` to `off`; using a non-zero value with these older versions leaves `named` vulnerable to CVE-2022-3924. Although it is possible to set the `recursive-clients` limit to a high number to reduce the likelihood of this scenario, this is not recommended; the limit on `recursive-clients` is important for preventing exhaustion of server resources. The limit cannot be disabled entirely.
Exploits
CNA: This flaw was discovered in internal testing. We are not aware of any active exploits.
Legacy QID Mappings
- 15142 ISC BIND Denial of Service (DoS) Vulnerability (CVE-2023-2911)
- 199435 Ubuntu Security Notification for Bind Vulnerabilities (USN-6183-1)
- 284044 Fedora Security Update for bind (FEDORA-2023-8e1ddb1fa2)
- 284045 Fedora Security Update for bind (FEDORA-2023-c0ff5a2f68)
- 284113 Fedora Security Update for bind (FEDORA-2023-1d526d551c)
- 355628 Amazon Linux Security Advisory for bind : ALAS2023-2023-240
- 6000172 Debian Security Update for bind9 (DSA 5439-1)
- 673912 EulerOS Security Update for bind (EulerOS-SA-2023-2837)
- 673993 EulerOS Security Update for bind (EulerOS-SA-2023-2854)
- 907393 Common Base Linux Mariner (CBL-Mariner) Security Update for bind (27237-1)