Bug 2453342 (CVE-2026-27853)

Summary: CVE-2026-27853 dnsdist: dnsdist: Denial of Service via crafted DNS responses
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in dnsdist. A remote attacker could send specially crafted DNS responses that, when processed by dnsdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code, may trigger an out-of-bounds write. This vulnerability can lead to a system crash, resulting in a denial of service.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2453421, 2453425    
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Description OSIDB Bzimport 2026-03-31 13:01:51 UTC 
An attacker might be able to trigger an out-of-bounds write by sending crafted DNS responses to a DNSdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code. In some cases the rewritten packet might become larger than the initial response and even exceed 65535 bytes, potentially leading to a crash resulting in denial of service.