AZL-103304

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Import Source
https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-103304.json
JSON Data
https://api.osv.dev/v1/vulns/AZL-103304
Upstream
Published
2026-09-18T18:17:11Z
Modified
2026-09-20T05:33:47Z
Summary
CVE-2026-69186 affecting package c-ares 1.30.0-2
Details

c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_parse() trusts the attacker-controlled ANCOUNT, NSCOUNT, and ARCOUNT fields before confirming that the DNS response contains enough bytes for the claimed records. Because process_answer() invokes parsing before transaction ID and question validation, a malicious DNS response can cause ares_dns_record_rr_prealloc() and ares_array_set_size() to reserve disproportionate heap memory for a tiny message. Repeated responses create large allocation and release cycles that can degrade or deny name resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.

References

Affected packages

Azure Linux:3 / c-ares

Package

Name
c-ares
Purl
pkg:rpm/azure-linux/c-ares

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Last Affected
1.30.0-2

Database specific

source
"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-103304.json"