CVE-2026-5946— Invalid handling of CLASS != IN
Possible ATT&CK Techniques 1AI
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I. Basic Information for CVE-2026-5946
Vulnerability Information
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Vulnerability Title
Invalid handling of CLASS != IN
Source: NVD (National Vulnerability Database)
Vulnerability Description
Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) — for example, `CHAOS` or `HESIOD`, or DNS messages that specify meta-classes (`ANY` or `NONE`) in the question section. Specially crafted requests reaching the affected code paths — recursion, dynamic updates (`UPDATE`), zone change notifications (`NOTIFY`), or processing of `IN`-specific record types in non-`IN` data — can cause assertion failures in `named`. This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
输入验证不恰当
Source: NVD (National Vulnerability Database)
Vulnerability Title
ISC BIND 9 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
ISC BIND 9是ISC组织的一个域名系统软件。 ISC BIND 9存在输入验证错误漏洞，该漏洞源于处理非Internet类DNS消息时存在缺陷，可能导致断言失败。以下版本受到影响：9.11.0版本至9.16.50版本、9.18.0版本至9.18.48版本、9.20.0版本至9.20.22版本、9.21.0版本至9.21.21版本、9.11.3-S1版本至9.16.50-S1版本、9.18.11-S1版本至9.18.48-S1版本和9.20.9-S1版本至9.20.22-S1版本。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-5946
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Vendor · 2Patch · 1Advisory · 1
- CVE-2026-5946: Invalid handling of CLASS != INvendor-advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-5946
Same Patch Batch · ISC · 2026-05-20 · 6 CVEs total
| CVE-2026-3039 | 7.5 HIGH | BIND 9 server memory exhaustion during GSS-API TKEY negotiation |
| CVE-2026-5947 | 7.5 HIGH | SIG(0) validation during query flood may lead to undefined behavior |
| CVE-2026-3593 | 7.4 HIGH | Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS implementation |
| CVE-2026-3592 | 5.3 MEDIUM | Amplification vulnerabilities via self-pointed glue records |
| CVE-2026-5950 | 5.3 MEDIUM | Unbounded resend loop in BIND 9 resolver |
IV. Related Vulnerabilities
Same product: BIND 9
- CVE-2026-5950
Unbounded resend loop in BIND 9 resolver - CVE-2026-5947
SIG(0) validation during query flood may lead to undefined b - CVE-2026-3593
Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS i - CVE-2026-3592
Amplification vulnerabilities via self-pointed glue records - CVE-2026-3039
BIND 9 server memory exhaustion during GSS-API TKEY negotiat
Same vendor: ISC
- CVE-2026-5950
Unbounded resend loop in BIND 9 resolver - CVE-2026-5947
SIG(0) validation during query flood may lead to undefined b - CVE-2026-3593
Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS i - CVE-2026-3592
Amplification vulnerabilities via self-pointed glue records - CVE-2026-3039
BIND 9 server memory exhaustion during GSS-API TKEY negotiat
V. Comments for CVE-2026-5946
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