CVE-2021-3694Network attack vector

Authenticated-user script execution via unescaped error feedback

Published Aug 23, 2021 · Updated Aug 3, 2024

Reflected XSS in affected LedgerSMB releases allows remote attackers to execute scripts in an authenticated user's browser through a crafted URL. The internal_server_error handler inserts attacker-controlled error feedback into its HTML response without escaping the message fields. Exploitation requires an authenticated target to follow the URL; a sufficiently privileged session enables information disclosure and actions with that user's authority.

CVSS severity8.2
High
EPSS probability2.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in affected LedgerSMB releases allows remote attackers to execute scripts in an authenticated user's browser through a crafted URL. The internal_server_error handler inserts attacker-controlled error feedback into its HTML response without escaping the message fields. Exploitation requires an authenticated target to follow the URL; a sufficiently privileged session enables information disclosure and actions with that user's authority.

The record

CVE
CVE-2021-3694
Published
Aug 23, 2021
Updated
Aug 3, 2024
Vendor
LedgerSMB
Product
LedgerSMB
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 23, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 <1.8.18

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

LedgerSMB · LedgerSMBversion=unspecified <1.8.18

Published CVSS scores

6.8NIST National Vulnerability DatabaseAV:N/AC:M/Au:N/C:P/I:P/A:P
8.2LedgerSMBCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
9.6NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

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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