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CVE-2021-23980

MEDIUM
6.1
CVSS Score
Published: February 16, 2023 at 12:00 AM UTC
Updated: June 17, 2026 at 03:39 AM UTC
1 product affected across 1 vendorBleach

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Severity
MEDIUM6.1
Exploit prediction
EPSS 0.5%
SSVC
PoC

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 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Bleach· Mozilla
95%
v < 3.3.0
Affected range stops below 3.3.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

ExploitIssue Tracking
Source: [email protected]
https://bugzilla.mozilla.org/show_bug.cgi?id=CVE-2021-23980
Vendor Advisory
Source: [email protected]
https://github.com/mozilla/bleach/security/advisories/GHSA-vv2x-vrpj-qqpq

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.1MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-79

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