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CVE Record

CVE-2020-8623: A flaw in native PKCS#11 code can lead to a remotely triggerable assertion failure in pk11.c

In BIND 9.10.0 -> 9.11.21, 9.12.0 -> 9.16.5, 9.17.0 -> 9.17.3, also affects 9.10.5-S1 -> 9.11.21-S1 of the BIND 9 Supported Preview Edition, An attacker that can reach a vulnerable system with a specially crafted query packet can trigger a crash. To be vulnerable, the system must: * be running BIND that was built with "--enable-native-pkcs11" * be signing one or more zones with an RSA key * be able to receive queries from a possible attacker

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This vulnerability can let an unauthenticated remote attacker crash certain BIND DNS servers. Business impact is availability: affected DNS service may stop responding if the server matches a narrow configuration involving native PKCS#11 and RSA zone signing.

Executive priority

Treat as high priority for DNS infrastructure because successful exploitation can cause outage. Prioritize externally reachable BIND servers first, especially those supporting DNSSEC signing with hardware or PKCS#11-backed RSA keys.

Technical view

CVE-2020-8623 is an assertion failure in BIND native PKCS#11 code in pk11.c. Exposure requires vulnerable BIND versions, build option --enable-native-pkcs11, at least one RSA-signed zone, and ability to receive attacker-supplied DNS queries. CVSS 3.1 is 7.5 for network-triggered high availability impact.

Likely exposure

Highest concern is internet-facing authoritative or recursive BIND infrastructure using native PKCS#11 with RSA zone signing. Standard BIND deployments without that build option or without RSA-signed zones are not described as vulnerable in the provided sources.

Exploitation context

The source bundle supports remote crash potential through a specially crafted query packet. It does not identify public exploitation, and KEV is false, so active exploitation should not be assumed from these sources.

Researcher notes

The vulnerability is configuration-dependent. The key triage question is not only BIND version, but whether native PKCS#11 is enabled and RSA zone signing is in use. Evidence provided does not include exploit code, exploitation in the wild, or a universal configuration workaround.

Mitigation direction

  • Inventory BIND versions and identify hosts within the affected version ranges.
  • Check whether BIND was built with --enable-native-pkcs11.
  • Apply ISC or operating-system vendor BIND security updates.
  • Review ISC guidance before changing PKCS#11 or DNSSEC signing configuration.
  • Restrict DNS query exposure to intended clients where operationally appropriate.

Validation and detection

  • Confirm whether any DNS service runs affected BIND 9 or Supported Preview Edition versions.
  • Verify native PKCS#11 build configuration on exposed BIND servers.
  • Identify zones signed with RSA keys on those servers.
  • Review package advisory status from ISC, Ubuntu, Debian, Fedora, Gentoo, SUSE, or appliance vendors.
  • Confirm updated systems no longer match the vulnerable version and configuration combination.
Prepared
Confidence
high
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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.

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CVE-2020-8623 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
10Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2020-8623Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
ISCBIND99.10.0, unspecified, 9.12.0, unspecified, 9.17.0, unspecified, 9.10.5-S1Listed
Weakness

CWE details

No CWE listed

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