CVE-2023-1718Public exploitNetwork attack vector

Unauthenticated service exhaustion via crafted file stream

Published Nov 1, 2023 · Updated Sep 5, 2024

Improper file-stream access in Bitrix24 22.0.300 and earlier allows unauthenticated remote attackers to exhaust server resources via upload requests. The /desktop_app/file.ajax.php uploadfile handler trusts the tmp_url field as a stream source; a php://stdout reference enters an infinite loop that exhausts server resources. A reachable on-premise web endpoint and no account or user interaction are required; exploitation interrupts service through resource exhaustion.

CVSS severity7.5
High
EPSS probability24.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper file-stream access in Bitrix24 22.0.300 and earlier allows unauthenticated remote attackers to exhaust server resources via upload requests. The /desktop_app/file.ajax.php uploadfile handler trusts the tmp_url field as a stream source; a php://stdout reference enters an infinite loop that exhausts server resources. A reachable on-premise web endpoint and no account or user interaction are required; exploitation interrupts service through resource exhaustion.

The record

CVE
CVE-2023-1718
Published
Nov 1, 2023
Updated
Sep 5, 2024
Vendor
Bitrix24
Product
Bitrix24
Classifications
CWE-835, CAPEC-545, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 5, 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=0 <=22.0.300

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Bitrix24 · Bitrix24version=0 <=22.0.300

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5STAR Labs SG Pte. Ltd.CVSS: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 exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
CAPEC-545Pull Data from System Resources
T1499.004Application or System Exploitation

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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