CVE-2023-41164Network attack vector

Service interruption via repeated whole-string Unicode decoding

Published Nov 3, 2023 · Updated Nov 4, 2025

Denial of service in Django 3.2 before 3.2.21, 4.1 before 4.1.11, and 4.2 before 4.2.5 allows remote attackers to interrupt service. The repercent_broken_unicode helper repeatedly decodes and rebuilds the entire byte string after each invalid Unicode fragment, causing excessive processing for inputs containing many such fragments. A network-facing application must pass attacker-controlled URI data to uri_to_iri(); exploitation affects availability without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability1.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Django 3.2 before 3.2.21, 4.1 before 4.1.11, and 4.2 before 4.2.5 allows remote attackers to interrupt service. The repercent_broken_unicode helper repeatedly decodes and rebuilds the entire byte string after each invalid Unicode fragment, causing excessive processing for inputs containing many such fragments. A network-facing application must pass attacker-controlled URI data to uri_to_iri(); exploitation affects availability without reported data disclosure or modification.

The record

CVE
CVE-2023-41164
Published
Nov 3, 2023
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-1284, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 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

6.9GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
7.5NIST NVDCVSS: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 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-1284Improper Validation of Specified Quantity in Input
T1499.004Application 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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