Security readout for executives and security teams
Plain-English summary
CVE-2021-4248 affects kapetan dns versions 6.0 and 6.1. The issue is weak randomness in request handling, which can make some DNS-related values easier to predict. The public record rates it medium, with remote attack possible but high attack complexity. Upgrade to version 7.0.0 is the documented fix.
Executive priority
Treat this as a planned medium-priority remediation, with faster handling for internet-facing DNS infrastructure. The business concern is predictability in security-sensitive request behavior, not confirmed widespread exploitation.
Technical view
The vulnerability is CWE-330, insufficient entropy in PRNG, associated with DNS/Protocol/Request.cs in kapetan dns up to 6.1.0. CVSS 3.1 is 5.6: network reachable, high complexity, no privileges or user interaction, and low confidentiality, integrity, and availability impact. Patch cf7105aa2aae90d6656088fe5a8ee1d5730773b6 addresses it in v7.0.0.
Likely exposure
Exposure appears limited to environments running kapetan dns 6.0 or 6.1. The source bundle provides no CPEs, deployment prevalence, or named downstream products, so asset discovery should focus on direct dependency and package inventory checks.
Exploitation context
The sources say the attack may be launched remotely, but complexity is high. The CVE is not listed as KEV in the bundle, and no cited source establishes active exploitation. Public details do not identify the exact affected runtime behavior beyond Request.cs entropy weakness.
Researcher notes
Evidence is sparse. The authoritative details identify insufficient PRNG entropy in Request.cs, affected versions 6.0 and 6.1, and remediation in v7.0.0. Avoid assuming exploitability details beyond the CVSS vector and remote/high-complexity characterization.
Mitigation direction
- Upgrade kapetan dns to version 7.0.0 or later.
- Prioritize externally reachable DNS services using affected versions.
- Review vendor release notes and patch cf7105aa2aae90d6656088fe5a8ee1d5730773b6.
- If upgrade timing is constrained, check vendor guidance for temporary mitigations.
Validation and detection
- Inventory systems and dependencies for kapetan dns 6.0 or 6.1.
- Confirm whether affected services are network reachable.
- Verify deployed code includes patch cf7105aa2aae90d6656088fe5a8ee1d5730773b6.
- Record upgrade evidence from package manifests, binaries, or deployment metadata.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-330: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-4248 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L2.23.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.6MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/kapetan/dns/pull/88CVE reference
- https://github.com/kapetan/dns/releases/tag/v7.0.0CVE reference
- https://github.com/kapetan/dns/commit/cf7105aa2aae90d6656088fe5a8ee1d5730773b6CVE reference
- https://vuldb.com/?id.216188CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use of Insufficiently Random Values
Use of Insufficiently Random Values represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.