CVE-2023-1540Network attack vector

Email enumeration via password-reset response discrepancy

Published Mar 21, 2023 · Updated Feb 25, 2025

Observable response discrepancy in Apache Answer before 1.0.6 allows remote attackers to identify registered email addresses. The RetrievePassWord service returns a UserNotFound error only when GetByEmail finds no account, causing the password-reset endpoint to distinguish unknown email addresses from registered ones. The endpoint requires no authentication or user interaction; successful probing discloses account existence but does not expose passwords or alter account privileges.

CVSS severity5.3
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable response discrepancy in Apache Answer before 1.0.6 allows remote attackers to identify registered email addresses. The RetrievePassWord service returns a UserNotFound error only when GetByEmail finds no account, causing the password-reset endpoint to distinguish unknown email addresses from registered ones. The endpoint requires no authentication or user interaction; successful probing discloses account existence but does not expose passwords or alter account privileges.

The record

CVE
CVE-2023-1540
Published
Mar 21, 2023
Updated
Feb 25, 2025
Vendor
The Apache Software Foundation
Product
Apache Answer
Classifications
CWE-204, CWE-203, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2025Record 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 <1.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache Answerversion=unspecified <1.0.6

Published CVSS scores

5.3huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-204Observable Response Discrepancy
CWE-203Observable Discrepancy
T1087Account Discovery

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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