SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-28957

An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3.

MEDIUM 6.1EPSS 4.04%

Does this matter?

Lower severity and a low EPSS score (4.04%). Track it; it rarely justifies an emergency change on its own.

Description

An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.

CVSS 3.1
6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
EPSS
4.04% probability · 90th percentile
CISA KEV
Not listed
Weakness
CWE-79
Affected
lxml/lxml · debian/debian linux · fedoraproject/fedora · netapp/snapcenter · oracle/zfs storage appliance kit
Source
cve@mitre.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.