CVE-2023-50387Network attack vector

Resolver denial of service via exhaustive signature validation

Published Feb 14, 2024 · Updated Nov 4, 2025

Algorithmic-complexity denial of service in DNSSEC-validating resolvers allows remote attackers to stall DNS service with crafted responses. Validators try every colliding DNSKEY against every RRSIG until one verifies or all combinations fail, multiplying costly signature checks without a work limit. An attacker controlling a DNSSEC-signed zone can trigger the loop through ordinary lookups, consuming CPU and halting DNS service for extended periods.

CVSS severity7.5
High
EPSS probability99.99%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic-complexity denial of service in DNSSEC-validating resolvers allows remote attackers to stall DNS service with crafted responses. Validators try every colliding DNSKEY against every RRSIG until one verifies or all combinations fail, multiplying costly signature checks without a work limit. An attacker controlling a DNSSEC-signed zone can trigger the loop through ordinary lookups, consuming CPU and halting DNS service for extended periods.

The record

CVE
CVE-2023-50387
Published
Feb 14, 2024
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 14, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA ADP VulnrichmentCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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