CVE-2026-27831Public exploitNetwork attack vector

Remote daemon crash via unterminated QNAME buffer

Published Feb 26, 2026 · Updated Feb 26, 2026

Heap-based out-of-bounds read in BlueDragonSecurity rldns 1.3 allows remote attackers to crash the DNS daemon with a crafted query. The QNAME parser allocates _name from label lengths without ensuring safe termination, then _count_octet_length() passes it to strlen(), which reads beyond the heap buffer. A network-reachable UDP or TCP DNS service is sufficient; the unauthenticated malformed query aborts the daemon without demonstrated data disclosure or code execution.

CVSS severity7.5
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based out-of-bounds read in BlueDragonSecurity rldns 1.3 allows remote attackers to crash the DNS daemon with a crafted query. The QNAME parser allocates _name from label lengths without ensuring safe termination, then _count_octet_length() passes it to strlen(), which reads beyond the heap buffer. A network-reachable UDP or TCP DNS service is sufficient; the unauthenticated malformed query aborts the daemon without demonstrated data disclosure or code execution.

The record

CVE
CVE-2026-27831
Published
Feb 26, 2026
Updated
Feb 26, 2026
Vendor
BlueDragonSecurity
Product
rldns
Classifications
CWE-125, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion== 1.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

BlueDragonSecurity · rldnsversion== 1.3

Published CVSS scores

7.5GitHub, Inc.CVSS: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 exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

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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