VulnerabilityPublished 3 Sep 2026Updated 12 Nov 2026

CVE-2026-93657: Hickory resolver · `Resolver::lookup` and `lookup_ip` returned records that failed DNSSEC validation

Affects hickory-resolverSource GCVE Database

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Authoritative record:CVE-2026-93657· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade to 0.26.2 soon.

Data as of 12 Nov 2026, 15:35 UTC

CVSS 4.0 base score

8.7High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 0.26.2

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade hickory-resolver to 0.26.2.

Affected software

Product	Affected	Fixed in
crates.iohickory-resolver`pkg:cargo/hickory-resolver`Other threats	Affected >=0.0.0-0 <0.26.2	Fixed in 0.26.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade hickory-resolver to version 0.26.2 or later, where the issue is fixed. In these versions, lookups with DNSSEC validation failures return an error and are not retried, preventing acceptance of bogus DNSSEC data. No additional mitigation is required once upgraded.

Description

A vulnerability in hickory-resolver versions before 0.26.2 caused DNSSEC validation failures to be ignored by Resolver::lookup() and Resolver::lookup_ip(), returning records marked as valid even when DNSSEC validation failed. This could lead applications that rely on successful lookups as proof of validation to accept forged or tampered DNS responses. The issue was fixed in version 0.26.2, where lookups with bogus DNSSEC records now fail with a specific error and are not retried.

Impact

Applications using affected versions of hickory-resolver with DNSSEC validation enabled could accept forged or tampered DNS responses if they rely solely on the success of Resolver::lookup() or Resolver::lookup_ip() calls without inspecting proof status. This undermines DNSSEC's protection against DNS spoofing and could lead to integrity issues in DNS-dependent operations. The vulnerability has a CVSS score of 7.5 (high severity) with no confidentiality or availability impact but high integrity impact.

Summary

In hickory-resolver versions prior to 0.26.2, when DNSSEC validation was enabled, the Resolver::lookup() and Resolver::lookup_ip() functions returned successful results (Ok) even if the DNSSEC validation failed, with the invalid status only indicated in each record's proof status. Applications that treated a successful lookup as validated data could be tricked into accepting forged or tampered DNS responses. Starting from version 0.26.2, the resolver returns a "DNSSEC validation failed" error (DnsError::DnssecBogus) for such cases, does not retry the query, and the hickory-server forwarder responds with SERVFAIL, preventing acceptance of invalid DNSSEC data.

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Nov 2026, 15:35 UTC

Technical details

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