CVE-2026-116013
Received Received - Intake

Improper Input Validation in OpenResty lua-resty-dns Resolver

Publication date: 2026-10-24

Last updated on: 2026-10-24

Assigner: VulnCheck

Description
OpenResty lua-resty-dns before 0.24 contains an improper input validation vulnerability in parse_section() and _decode_name() that fails to check resource record lengths against the received message. Attackers controlling or spoofing a queried nameserver can send truncated record headers or RDATA, raising uncaught Lua exceptions in resolver:query() that abort requests and break name resolution.

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Meta Information

Published
2026-10-24
Last Modified
2026-10-24
Generated
2026-10-24
AI Q&A
2026-10-24
EPSS Evaluated
N/A
NVD
CVE-2026-116013
EUVD
EUVD-2026-109271

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
openresty lua-resty-dns 0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-130 The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

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Executive Summary

This vulnerability is in OpenResty's lua-resty-dns library before version 0.24. It involves improper input validation in DNS response parsing functions like parse_section() and _decode_name(). Attackers controlling a nameserver can send truncated DNS records, causing uncaught Lua exceptions that abort requests and break name resolution, leading to a denial-of-service condition.

Detection Guidance

Monitor for DNS resolution failures or uncaught Lua exceptions in resolver:query() when processing DNS responses. Check logs for truncated record headers or RDATA errors in lua-resty-dns versions before 0.24. Use network traffic analysis tools like tcpdump or Wireshark to inspect DNS responses for malformed records.

Impact Analysis

This vulnerability can cause denial-of-service by disrupting DNS resolution, leading to failed requests or application crashes. Attackers may exploit it to crash services relying on the library for DNS queries, potentially affecting web applications, APIs, or other network-dependent systems using OpenResty.

Mitigation Strategies

Upgrade lua-resty-dns to version 0.24 or later. Apply the patch from the GitHub pull request #83. Validate DNS responses for proper record lengths and reject malformed data. Monitor for DoS conditions caused by DNS resolution failures.

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