{"id":"CVE-2023-26438","url":"https://www.cyber-defence.io/tools/cve/CVE-2023-26438","generatedAt":"2026-10-23T08:55:57.776Z","title":"External service lookups for a number of protocols were vulnerable to a time-of-check/time-of-use (TOCTOU) weakness, involving the JDK DNS cache.","description":"External service lookups for a number of protocols were vulnerable to a time-of-check/time-of-use (TOCTOU) weakness, involving the JDK DNS cache. Attackers that were timing DNS cache expiry correctly were able to inject configuration that would bypass existing network deny-lists. Attackers could exploit this weakness to discover the existence of restricted network infrastructure and service availability. Improvements were made to include deny-lists not only during the check of the provided connection data, but also during use. No publicly available exploits are known.\n\n","published":"2023-08-02T13:15:10.000Z","lastModified":"2026-06-17T05:43:20.000Z","status":"Modified","sourceIdentifier":"security@open-xchange.com","cvss":{"version":"3.1","score":3.1,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N"},"cwe":["CWE-918","CWE-367"],"affected":["open-xchange/open-xchange appsuite backend"],"epss":{"score":0.006,"percentile":0.48012,"date":"2026-10-22","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.60%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"http://packetstormsecurity.com/files/173943/OX-App-Suite-SSRF-SQL-Injection-Cross-Site-Scripting.html","tags":["Third Party Advisory","VDB Entry"],"source":"security@open-xchange.com"},{"url":"http://seclists.org/fulldisclosure/2023/Aug/8","tags":["Mailing List","Third Party Advisory"],"source":"security@open-xchange.com"},{"url":"https://documentation.open-xchange.com/appsuite/security/advisories/csaf/2023/oxas-adv-2023-0003.json","source":"security@open-xchange.com"},{"url":"https://software.open-xchange.com/products/appsuite/doc/Release_Notes_for_Patch_Release_6230_7.10.6_2023-05-02.pdf","tags":["Release Notes"],"source":"security@open-xchange.com"},{"url":"http://packetstormsecurity.com/files/173943/OX-App-Suite-SSRF-SQL-Injection-Cross-Site-Scripting.html","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://seclists.org/fulldisclosure/2023/Aug/8","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://documentation.open-xchange.com/appsuite/security/advisories/csaf/2023/oxas-adv-2023-0003.json","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://software.open-xchange.com/products/appsuite/doc/Release_Notes_for_Patch_Release_6230_7.10.6_2023-05-02.pdf","tags":["Release Notes"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-26438","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}