CVE-2021-23648Public exploitNetwork attack vector

Script execution via encoded URL scheme

Published Mar 16, 2022 · Updated Sep 16, 2024

Cross-site scripting in Braintree sanitize-url before 6.0.0 allows remote attackers to execute script through an HTML-encoded URL. The sanitizeUrl function checked the still-encoded scheme and returned it unchanged, so server rendering decoded a hidden javascript scheme only after sanitization. Exploitation requires an application to place attacker-controlled sanitized output into server-rendered HTML and a user to open the resulting link, enabling script execution in that page's context.

CVSS severity5.4
Medium
EPSS probability1.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Braintree sanitize-url before 6.0.0 allows remote attackers to execute script through an HTML-encoded URL. The sanitizeUrl function checked the still-encoded scheme and returned it unchanged, so server rendering decoded a hidden javascript scheme only after sanitization. Exploitation requires an application to place attacker-controlled sanitized output into server-rendered HTML and a user to open the resulting link, enabling script execution in that page's context.

The record

CVE
CVE-2021-23648
Published
Mar 16, 2022
Updated
Sep 16, 2024
Vendor
Braintree
Product
sanitize-url
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <6.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Braintree · sanitize-urlversion=unspecified <6.0.0

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.1Snyk CNACVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
5.4GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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