CVE-2025-31498Network attack vector

Use-after-free via immediate query resend

Published Apr 8, 2025 · Updated Apr 8, 2025

Use-after-free in read_answers() in c-ares 1.32.3 through 1.34.4 allows attackers to corrupt memory via failed query resends. During answer parsing, process_answer() can immediately resend a re-enqueued query; a send failure closes the connection that read_answers() then continues using. Remote reachability requires control of the upstream DNS server plus ICMP UNREACHABLE flooding, while local users can induce send() or write() failure; the remote scenario remains untested.

CVSS severity8.3
High
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in read_answers() in c-ares 1.32.3 through 1.34.4 allows attackers to corrupt memory via failed query resends. During answer parsing, process_answer() can immediately resend a re-enqueued query; a send failure closes the connection that read_answers() then continues using. Remote reachability requires control of the upstream DNS server plus ICMP UNREACHABLE flooding, while local users can induce send() or write() failure; the remote scenario remains untested.

The record

CVE
CVE-2025-31498
Published
Apr 8, 2025
Updated
Apr 8, 2025
Vendor
c-ares Project
Product
c-ares
Classifications
CWE-416, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 1.32.3, < 1.34.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

c-ares Project · c-aresversion=>= 1.32.3, < 1.34.5

Published CVSS scores

8.3GitHub, Inc.CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA: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.

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

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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