Public proof of conceptFix available

CVE-2023-28853

Q: Is CVE-2023-28853 actively exploited?

A proof-of-concept exploit exists for CVE-2023-28853, but active exploitation has not been confirmed at this time.

Q: What is the CVSS score for CVE-2023-28853?

CVE-2023-28853 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

A public proof of concept exists; no exploitation attested.

Published2023-04-04
Fixed in4.1.2 · 4.0.4 · 3.5.8
WeaknessCWE-74 · CWE-90

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Mastodon is a free, open-source social network server based on ActivityPub Mastodon allows configuration of LDAP for authentication. Starting in version 2.5.0 and prior to versions 3.5.8, 4.0.4, and 4.1.2, the LDAP query made during login is insecure and the attacker can perform LDAP injection attack to leak arbitrary attributes from LDAP database. This issue is fixed in versions 3.5.8, 4.0.4, and 4.1.2.

Timeline

dates in UTC

2023-04-0422:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-28853?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-28853?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Joinmastodon mastodon

Branch	Affected	Fixed in	Source
4.1	≥ 4.1.0, < 4.1.2	4.1.2	NVD · OSV
4.0	≥ 4.0.0, < 4.0.4	4.0.4	NVD · OSV
3.5	≥ 2.5.0, < 3.5.8	3.5.8	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Joinmastodon mastodon to 4.1.2 · 4.0.4 · 3.5.8

Advisories and patches

github.comPatch
github.comRelease Notes
github.comRelease Notes
github.comRelease Notes
github.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionpoc2025-02-10
OpenCVESSVC decisionpoc—
CNACVSS 3.17.7read 2026-10-23
NVDCVSS 3.16.5read 2026-10-23
CNAweakness (CWE)CWE-90read 2026-10-23
NVDweakness (CWE)CWE-74read 2026-10-23
FIRST EPSSEPSS score1.3 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Published: 2023-04-04
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2023-28853?

Is CVE-2023-28853 actively exploited?

A proof-of-concept exploit exists for CVE-2023-28853, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2023-28853?

CVE-2023-28853 has a CVSS v3 base score of 6.5 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

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Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

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