CVE-2023-28853Public exploitNetwork attack vector

LDAP attribute disclosure via unescaped login filter

Published Apr 4, 2023 · Updated Feb 13, 2025

LDAP injection in Mastodon's LDAP login flow before 3.5.8, 4.0.4, or 4.1.2 allows remote authenticated users to read LDAP attributes. authenticate_with_ldap formats the submitted email directly into LDAP_SEARCH_FILTER without escaping LDAP metacharacters, letting a crafted login alter the search predicate. LDAP authentication and attacker-controlled account credentials are required; differing login results form a one-bit oracle, while account takeover was not demonstrated.

CVSS severity7.7
High
EPSS probability1.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

LDAP injection in Mastodon's LDAP login flow before 3.5.8, 4.0.4, or 4.1.2 allows remote authenticated users to read LDAP attributes. authenticate_with_ldap formats the submitted email directly into LDAP_SEARCH_FILTER without escaping LDAP metacharacters, letting a crafted login alter the search predicate. LDAP authentication and attacker-controlled account credentials are required; differing login results form a one-bit oracle, while account takeover was not demonstrated.

The record

CVE
CVE-2023-28853
Published
Apr 4, 2023
Updated
Feb 13, 2025
Vendor
Mastodon
Product
Mastodon
Classifications
CWE-74, CWE-90, T1213.006
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=>= 2.5.0, < 3.5.8
  2. Affected versionversion=>= 4.0.0, < 4.0.4
  3. Affected versionversion=>= 4.1.0, < 4.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mastodon · Mastodonversion=>= 2.5.0, < 3.5.8; version=>= 4.0.0, < 4.0.4; version=>= 4.1.0, < 4.1.2

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
7.7GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CWE-90Improper Neutralization of Special Elements used in an LDAP Query ('LDAP Injection')
T1213.006Data from Information Repositories: Databases

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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