CVE-2022-45061Network attack vector

CPU denial of service via quadratic IDNA decoding

Published Nov 9, 2022 · Updated Nov 3, 2025

Python before 3.11.1 allows remote attackers to cause CPU denial of service via crafted oversized IDNA hostnames. The IDNA decoder applies a quadratic-time path before enforcing hostname-label limits, so an extremely long attacker-controlled name consumes excessive CPU during decoding. The attack requires a client to process attacker-supplied host data, such as a redirect Location header; impact is service interruption through CPU exhaustion, without reported confidentiality or integrity effects.

CVSS severity7.5
High
EPSS probability2.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Python before 3.11.1 allows remote attackers to cause CPU denial of service via crafted oversized IDNA hostnames. The IDNA decoder applies a quadratic-time path before enforcing hostname-label limits, so an extremely long attacker-controlled name consumes excessive CPU during decoding. The attack requires a client to process attacker-supplied host data, such as a redirect Location header; impact is service interruption through CPU exhaustion, without reported confidentiality or integrity effects.

The record

CVE
CVE-2022-45061
Published
Nov 9, 2022
Updated
Nov 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 9, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 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

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

T1499Endpoint Denial of Service

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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