CVE-2022-2526Network attack vector

Remote memory corruption via DNS stream use-after-free

Published Sep 9, 2022 · Updated Aug 3, 2024

Use-after-free in systemd-resolved 240 allows remote attackers to corrupt memory via crafted DNS stream callbacks. The on_stream_io() and dns_stream_complete() functions fail to increment the DnsStream reference count before invoking callbacks that can unreference the object, leaving later dereferences pointed at freed memory. The DNS resolver must process attacker-controlled network traffic; exploitation can crash the service or enable broader memory corruption, with high confidentiality and integrity impact reported by NVD.

CVSS severity9.8
Critical
EPSS probability1.32%
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 systemd-resolved 240 allows remote attackers to corrupt memory via crafted DNS stream callbacks. The on_stream_io() and dns_stream_complete() functions fail to increment the DnsStream reference count before invoking callbacks that can unreference the object, leaving later dereferences pointed at freed memory. The DNS resolver must process attacker-controlled network traffic; exploitation can crash the service or enable broader memory corruption, with high confidentiality and integrity impact reported by NVD.

The record

CVE
CVE-2022-2526
Published
Sep 9, 2022
Updated
Aug 3, 2024
Vendor
systemd
Product
systemd
Classifications
CWE-416, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 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?

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

  1. Affected versionversion=systemd 240

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

systemd · systemdversion=systemd 240

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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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 exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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