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Vulnerability record · CVE-2023-26432 · published 20 June 2023

CVE-2023-26432: Open-xchange appsuite backend uncontrolled resource consumption vulnerability

Open Xchange · Open Xchange Appsuite Backend

When adding an external mail account, processing of SMTP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue SMTP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted SMTP server response to reasonable length/size. No publicly available exploits are known.

4.3 CVSS 3.1 Medium EPSS 1.1% · top 34.0% CWE-400 · Uncontrolled resource consumption
4.3CVSS 3.1 base score
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

Description

When adding an external mail account, processing of SMTP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue SMTP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted SMTP server response to reasonable length/size. No publicly available exploits are known.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://packetstormsecurity.com/files/173083/OX-App-Suite-SSRF-Resource-Consumption-Command-Injection.html Third Party AdvisoryVDB Entry
http://seclists.org/fulldisclosure/2023/Jun/8 Mailing ListThird Party Advisory
https://documentation.open-xchange.com/appsuite/security/advisories/csaf/2023/oxas-adv-2023-0002.json
https://software.open-xchange.com/products/appsuite/doc/Release_Notes_for_Patch_Release_6219_7.10.6_2023-03-20.pdf Release Notes
http://packetstormsecurity.com/files/173083/OX-App-Suite-SSRF-Resource-Consumption-Command-Injection.html Third Party AdvisoryVDB Entry
http://seclists.org/fulldisclosure/2023/Jun/8 Mailing ListThird Party Advisory
https://documentation.open-xchange.com/appsuite/security/advisories/csaf/2023/oxas-adv-2023-0002.json
https://software.open-xchange.com/products/appsuite/doc/Release_Notes_for_Patch_Release_6219_7.10.6_2023-03-20.pdf Release Notes

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2023-26443Open-xchange appsuite backend sql injection vulnerabilityFull-text autocomplete search allows user-provided SQL syntax to be injected to SQL statements. With existing sanitization in place, this can be abus…EPSS 0.82%8.8CVE-2023-26436Open-xchange appsuite backend code injection vulnerabilityAttackers with access to the "documentconverterws" API were able to inject serialized Java objects, that were not properly checked during deserializa…EPSS 1.3%7.5CVE-2023-26451Open-xchange appsuite backend vulnerabilityFunctions with insufficient randomness were used to generate authorization tokens of the integrated oAuth Authorization Service. Authorization codes …EPSS 1.2%6.5CVE-2023-26428Open-xchange appsuite backend insecure direct object reference vulnerabilityAttackers can successfully request arbitrary snippet IDs, including E-Mail signatures of other users within the same context. Signatures of other use…EPSS 0.98%6.1CVE-2016-6846Open-xchange documentconverter-api cross-site scripting vulnerabilityCross-site scripting (XSS) vulnerability in Open-Xchange (OX) AppSuite backend before 7.6.2-rev59, 7.8.0 before 7.8.0-rev38, 7.8.2 before 7.8.2-rev8;…EPSS 1.2%5.3CVE-2023-26429Open-xchange appsuite backend command injection vulnerabilityControl characters were not removed when exporting user feedback content. This allowed attackers to include unexpected content via user feedback and …EPSS 0.79%5.0CVE-2023-26435Open-xchange appsuite backend server-side request forgery (ssrf) vulnerabilityIt was possible to call filesystem and network references using the local LibreOffice instance using manipulated ODT documents. Attackers could disco…EPSS 0.78%4.3CVE-2023-26430Open-xchange appsuite backend command injection vulnerabilityAttackers with access to user accounts can inject arbitrary control characters to SIEVE mail-filter rules. This could be abused to access SIEVE exten…EPSS 0.75%

Source: NIST National Vulnerability Database (record CVE-2023-26432), CISA KEV, FIRST EPSS (scores of 2026-10-13). This page is refreshed as NVD updates the record.