CVE-2021-40923Public exploitNetwork attack vector

Unauthenticated browser script execution via unescaped installer email

Published Oct 1, 2021 · Updated Aug 4, 2024

Reflected cross-site scripting in Pixeline Bugs 1.8 and earlier allows remote attackers to run script in a victim's browser via email. install/index.php writes the POST email value directly into an HTML input value attribute without escaping, allowing attribute termination and script injection. Exploitation requires access to the configured installation workflow and a victim induced to submit a crafted form; injected script runs in the Bugs origin.

CVSS severity6.1
Medium
EPSS probability0.84%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected cross-site scripting in Pixeline Bugs 1.8 and earlier allows remote attackers to run script in a victim's browser via email. install/index.php writes the POST email value directly into an HTML input value attribute without escaping, allowing attribute termination and script injection. Exploitation requires access to the configured installation workflow and a victim induced to submit a crafted form; injected script runs in the Bugs origin.

The record

CVE
CVE-2021-40923
Published
Oct 1, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 1, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1204.001Malicious Link

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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