synced 6 MIN AGO
01 Record

CVE-2021-23980

A mutation XSS affects users calling bleach.clean with all of: svg or math in the allowed tags p or br in allowed tags style, title, noscript, script, textarea, noframes, iframe, or xmp in allowed

MediumPUBLISHEDCNA: mozilla
CNA base score6.1 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

02 Description

A mutation XSS affects users calling bleach.clean with all of: svg or math in the allowed tags p or br in allowed tags style, title, noscript, script, textarea, noframes, iframe, or xmp in allowed

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.48% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 41.3% of scored records. A rank, not a probability.
NVD base score
6.1 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2023-02-16 00:00Z3 YR AGO
Last updated
2025-03-19 15:18Z1 YR AGO
Reserved
2021-01-13
Assigning CNA
mozilla
Record state
PUBLISHED
Severity
Medium (CVSS 6.1)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weaknesses
  • CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base
Data version
5.1
Document digest
c480afade3b11a43b7cad9c671a43b2c244a6c617a77b5b4f8473c268d6c977e

05 Affected products

VendorProductVersionsPlatforms
MozillaMozilla Bleach< 3.3.0—

06 References

07 Fixed in

Debian 12

  • python-bleach
    Fixed in 3.2.1-2.1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • python-bleach
    Fixed in 3.2.1-2.1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • python-bleach
    Fixed in 3.2.1-2.1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 16.04 LTS

  • python-bleach
    Fixed in 1.4.2-1ubuntu0.1~esm1
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 18.04 LTS

  • python-bleach
    Fixed in 2.1.2-1ubuntu0.1~esm1
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 20.04 LTS

  • python-bleach
    Fixed in 3.1.1-1ubuntu0.1~esm1
    Available with Ubuntu Pro: https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.