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Fencer Intel
low 2.4

CVE-2020-4049 json

Authenticated self-XSS via theme uploads in WordPress

published 6y ago modified 2mo ago also BIT-wordpress-2020-4049 , BIT-wordpress-multisite-2020-4049 , EUVD-2020-25307 , GHSA-87h4-phjv-rm6p

cvss
2.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

In affected versions of WordPress, when uploading themes, the name of the theme folder can be crafted in a way that could lead to JavaScript execution in /wp-admin on the themes page. This does require an admin to upload the theme, and is low severity self-XSS. This has been patched in version 5.4.2, along with all the previously affected versions via a minor release (5.3.4, 5.2.7, 5.1.6, 5.0.10, 4.9.15, 4.8.14, 4.7.18, 4.6.19, 4.5.22, 4.4.23, 4.3.24, 4.2.28, 4.1.31, 4.0.31, 3.9.32, 3.8.34, 3.7.34).

Patch / fix

  • bitnami wordpress 3.7.34, 3.8.34, 3.9.32, 4.0.31, 4.1.31, 4.2.28, 4.3.24, 4.4.23, 4.5.22, 4.6.19, 4.7.18, 4.8.14, 4.9.15, 5.0.10, 5.1.6, 5.2.7, 5.3.4, 5.4.2
  • bitnami wordpress-multisite 3.7.34, 3.8.34, 3.9.32, 4.0.31, 4.1.31, 4.2.28, 4.3.24, 4.4.23, 4.5.22, 4.6.19, 4.7.18, 4.8.14, 4.9.15, 5.0.10, 5.1.6, 5.2.7, 5.3.4, 5.4.2
  • wordpress wordpress 3.7.34, 3.8.34, 3.9.32, 4.0.31, 4.1.31, 4.2.28, 4.3.24, 4.4.23, 4.5.22, 4.6.19, 4.7.18, 4.8.14, 4.9.15, 5.0.10, 5.1.6, 5.2.7, 5.3.4, 5.4.2
  • wordpress Debian 14, Debian 13, Debian 12 5.4.2+dfsg1-1

debian advisories DEBIAN-CVE-2020-4049

Is CVE-2020-4049 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-4049 updated cvss 2.4

wordpress: authenticated self-XSS via theme uploads

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.53% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 2.4 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
NVD 3.1 2.4 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
NVD 2.0 3.5 AV:N/AC:M/Au:S/C:N/I:P/A:N
OSV 3.1 2.4 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami wordpress
>=3.7.0, <3.7.34
>=3.8.0, <3.8.34
>=3.9.0, <3.9.32
>=4.0.0, <4.0.31
>=4.1.0, <4.1.31
>=4.2.0, <4.2.28
>=4.3.0, <4.3.24
>=4.4.0, <4.4.23
>=4.5.0, <4.5.22
>=4.6.0, <4.6.19
>=4.7.0, <4.7.18
>=4.8.0, <4.8.14
>=4.9.0, <4.9.15
>=5.0.0, <5.0.10
>=5.1.0, <5.1.6
>=5.2.0, <5.2.7
>=5.3.0, <5.3.4
>=5.4.0, <5.4.2
3.7.34
3.8.34
3.9.32
4.0.31
4.1.31
4.2.28
4.3.24
4.4.23
4.5.22
4.6.19
4.7.18
4.8.14
4.9.15
5.0.10
5.1.6
5.2.7
5.3.4
5.4.2
bitnami wordpress-multisite
>=3.7.0, <3.7.34
>=3.8.0, <3.8.34
>=3.9.0, <3.9.32
>=4.0.0, <4.0.31
>=4.1.0, <4.1.31
>=4.2.0, <4.2.28
>=4.3.0, <4.3.24
>=4.4.0, <4.4.23
>=4.5.0, <4.5.22
>=4.6.0, <4.6.19
>=4.7.0, <4.7.18
>=4.8.0, <4.8.14
>=4.9.0, <4.9.15
>=5.0.0, <5.0.10
>=5.1.0, <5.1.6
>=5.2.0, <5.2.7
>=5.3.0, <5.3.4
>=5.4.0, <5.4.2
3.7.34
3.8.34
3.9.32
4.0.31
4.1.31
4.2.28
4.3.24
4.4.23
4.5.22
4.6.19
4.7.18
4.8.14
4.9.15
5.0.10
5.1.6
5.2.7
5.3.4
5.4.2

Affected products

  • WordPress wordpress-develop

Classification

Weakness
  • CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page
  • CWE-79 Improper Neutralization of Input During Web Page Generation
Technology feeds

References

Sources

Fencer Intel 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.

The maintainers of WordPress/wordpress-develop published their own advisory on GitHub. Reviewed sources take precedence over it.