Skip to content
Fencer Vulns
low 2.2

CVE-2020-4071 json

Timing attack on django-basic-auth-ip-whitelist

published 2020-06-23 6 y ago modified 2026-07-08 4 mo ago also GHSA-m38j-pmg3-v5x5 , PYSEC-2020-37 , EUVD-2020-0062

cvss
2.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

In django-basic-auth-ip-whitelist before 0.3.4, a potential timing attack exists on websites where the basic authentication is used or configured, i.e. BASIC_AUTH_LOGIN and BASIC_AUTH_PASSWORD is set. Currently the string comparison between configured credentials and the ones provided by users is performed through a character-by-character string comparison. This enables a possibility that attacker may time the time it takes the server to validate different usernames and password, and use this knowledge to work out the valid credentials. This attack is understood not to be realistic over the Internet. However, it may be achieved from within local networks where the website is hosted, e.g. from inside a data centre where a website's server is located. Sites protected by IP address whitelisting only are unaffected by this vulnerability. This vulnerability has been fixed on version 0.3.4 of django-basic-auth-ip-whitelist. Update to version 0.3.4 as soon as possible and change basic authentication username and password configured on a Django project using this package. A workaround without upgrading to version 0.3.4 is to stop using basic authentication and use the IP whitelisting component only. It can be achieved by not setting BASIC_AUTH_LOGIN and BASIC_AUTH_PASSWORD in Django project settings.

Patch / fix

  • pypi django-basic-auth-ip-whitelist 0.3.4
  • django-basic-auth-ip-whitelist_project django-basic-auth-ip-whitelist 0.3.4

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 2.2 CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
NVD 3.1 2.4 CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.1 2.2 CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
pypi django-basic-auth-ip-whitelist
<0.3.4
0.3.4

Affected products

  • tm-kn django-basic-auth-ip-whitelist

Classification

Weakness
  • CWE-208 Observable Timing Discrepancy

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.