CVE-2023-50455Network attack vector

Unauthenticated service interruption via verification request flooding

Published Dec 10, 2023 · Updated Aug 28, 2024

Denial of service in Zammad before 6.2.0 allows remote attackers to flood a known address with verification requests and email. The email address verification feature accepts repeated requests for the same known address without rate limiting, generating a new email for each request. The endpoint requires no authentication; sustained requests interrupt service while spamming the targeted mailbox.

CVSS severity7.5
High
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in Zammad before 6.2.0 allows remote attackers to flood a known address with verification requests and email. The email address verification feature accepts repeated requests for the same known address without rate limiting, generating a new email for each request. The endpoint requires no authentication; sustained requests interrupt service while spamming the targeted mailbox.

The record

CVE
CVE-2023-50455
Published
Dec 10, 2023
Updated
Aug 28, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-770, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 28, 2024Record 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?

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

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 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-770Allocation of Resources Without Limits or Throttling
T1499.002Endpoint Denial of Service: Service Exhaustion Flood

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo