CVE-2026-5947
May 21, 2026, 3:24 p.m.
7.5
High
Description
Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursive-clients" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message.
This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1.
BIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Isc |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-362
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | isc | bind | / | / | / | / | - | / | / | / |
| a | isc | bind | / | / | / | / | - | / | / | / |
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: NETWORK
- Attack Complexity: LOW
- Privileges Required: NONE
- Scope: UNCHANGED
- Confidentiality Impact: NONE
- Integrity Impact: NONE
- Availability Impact: HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Timeline
Published: May 20, 2026, 1:16 p.m.
Last Modified: May 21, 2026, 3:24 p.m.
Last Modified: May 21, 2026, 3:24 p.m.
Status : Analyzed
CVE has been marked for Analysis. Normally once in this state the CVE will be analyzed by NVD staff within 24 hours.
More infoSource
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.