CVE-2021-23980

Exp

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 tags the keyword argument strip_comments=False Note: none of the above tags are in the default allowed tags and strip_comments defaults to True.

Published: 2023-02-16 Last update: 2025-03-19 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-23980 is rated High Exploit Risk (62/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.47%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-23980

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-23980

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-02-24 0.41% 0.47% +0.07%
2 2026-01-14 0.34% 0.41% +0.07%
3 2025-12-07 — 0.34% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-23980

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2021-23980

GitHub Security Advisory for CVE-2021-23980

OS Trackers for CVE-2021-23980

vendor priority summary link
alpine — CVE-2021-23980: 1 source package rows (py3-bleach); 7 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2021-23980
debian not yet assigned CVE-2021-23980 not yet assigned priority: Debian including 1 source packages (python-bleach), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-23980
redhat medium — https://access.redhat.com/security/cve/CVE-2021-23980
suse medium CVE-2021-23980 severity moderate: SUSE including 12 source package names (python2-bleach-3.1.5-bp152.2.4.1, python2-bleach-3.1.5-lp152.2.3.1, …), 12 product×package rows across 5 product lines (SUSE Linux Enterprise Module for Python 3 15 SP6, SUSE Linux Enterprise Server 16.0, … (5 product lines)): Fixed 12. https://www.suse.com/security/cve/CVE-2021-23980/
ubuntu medium CVE-2021-23980 medium priority: Ubuntu including 1 source packages (python-bleach), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 8, released 4, not-affected 3, DNE 1. https://ubuntu.com/security/CVE-2021-23980

Affected software / configurations for CVE-2021-23980

Vendor Product Version Raw CPE
mozilla bleach < 3.3.0 cpe:2.3:a:mozilla:bleach:*:*:*:*:*:*:*:*

References for CVE-2021-23980

cvelogic Threat Intelligence