CVE-2022-33993Public exploitNetwork attack vector

Connection hijacking via special-character DNS cache poisoning

Published Aug 15, 2022 · Updated Aug 3, 2024

DNS cache poisoning in DNRD 2.20.3 allows remote attackers to redirect client connections through crafted domain names. The forwarder misinterprets zero bytes or period characters in DNS queries or answers, then caches attacker-supplied addresses under domain names the attacker does not control. Exploitation requires an attacker-controlled script or website to be loaded by a client using the vulnerable forwarder, after which poisoned answers can hijack that client's connections.

CVSS severity5.3
Medium
EPSS probability0.92%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DNS cache poisoning in DNRD 2.20.3 allows remote attackers to redirect client connections through crafted domain names. The forwarder misinterprets zero bytes or period characters in DNS queries or answers, then caches attacker-supplied addresses under domain names the attacker does not control. Exploitation requires an attacker-controlled script or website to be loaded by a client using the vulnerable forwarder, after which poisoned answers can hijack that client's connections.

The record

CVE
CVE-2022-33993
Published
Aug 15, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 15, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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

T1557Adversary-in-the-Middle

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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