CVE-2023-31893Public exploitNetwork attack vector

Service interruption via open recursive DNS

Published Jun 5, 2023 · Updated Jan 31, 2025

DNS recursion in Telefônica Brasil Vivo Play firmware 2023.04.04.01.06.15 allows remote attackers to interrupt the device's service. The DNS service answers recursive queries for arbitrary external names, and sustained unauthenticated traffic to port 53 takes the device offline. Network reachability to the DNS listener is sufficient; the published demonstration reports service loss, not data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.87%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DNS recursion in Telefônica Brasil Vivo Play firmware 2023.04.04.01.06.15 allows remote attackers to interrupt the device's service. The DNS service answers recursive queries for arbitrary external names, and sustained unauthenticated traffic to port 53 takes the device offline. Network reachability to the DNS listener is sufficient; the published demonstration reports service loss, not data disclosure or modification.

The record

CVE
CVE-2023-31893
Published
Jun 5, 2023
Updated
Jan 31, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-674, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 5, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 31, 2025Record 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

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-674Uncontrolled Recursion
T1499Endpoint Denial of Service

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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