CVE-2023-26434

Severity: medium (CVSS 4.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-06-20 · updated 2026-06-17
Weakness: CWE-400

Description

When adding an external mail account, processing of POP3 "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue POP3 service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted POP3 server response to reasonable length/size. No publicly available exploits are known.

Affected products

Open-Xchange Appsuite Backend: before 7.10.6; 7.10.6, 7.10.6-revision_39 — fixed in 7.10.6

How to fix

Upgrade to a fixed version: Open-Xchange Appsuite Backend 7.10.6. Check the vendor advisory for mitigations.

References

http://packetstormsecurity.com/files/173083/OX-App-Suite-SSRF-Resource-Consumption-Command-Injection.html
http://seclists.org/fulldisclosure/2023/Jun/8
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
http://packetstormsecurity.com/files/173083/OX-App-Suite-SSRF-Resource-Consumption-Command-Injection.html
http://seclists.org/fulldisclosure/2023/Jun/8
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

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