{"id":"CVE-2026-107581","summary":"Inefficient Algorithmic Complexity in hMailServer","details":"Progressive Robot hMailServer 6.0.0 through 6.3.5 processes several IMAP commands from a signed-in account in time quadratic in the command's length or in the number of elements it names, and can be made to hold memory out of proportion to a command. The FETCH data-item parser normalised a BODY[] section with a case-insensitive string replacement that copied the whole item per occurrence and split the item list by repeatedly copying the remainder of the command; the server's case-insensitive search compared a needle afresh at every position, so a long SEARCH TEXT key over a message cost the product of the two lengths; SEARCH message sets and the saved-result marker ($), SORT criteria, HEADER.FIELDS name lists and UID ranges were each read once per message rather than once per command; and a FETCH naming a message's sections very many times read and held every section in memory before sending any. An IMAP command may continue past one line through non-synchronizing literals, so one command can reach about eleven megabytes. The IMAP worker threads are a small pool shared with SMTP and POP3, so a signed-in user sending such commands can make the IMAP, SMTP and POP3 services stop responding (CWE-407) and can consume excessive memory (CWE-400).","modified":"2026-10-10T02:47:22.838176439Z","published":"2026-10-08T11:47:16.084Z","database_specific":{"cwe_ids":["CWE-407"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107581.json","cna_assigner":"GitLab"},"references":[{"type":"WEB","url":"https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"},{"type":"WEB","url":"https://gitlab.com/hmailserver/hmailserver/-/work_items/68"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107581.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107581"},{"type":"PACKAGE","url":"https://gitlab.com/hmailserver/hmailserver"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://gitlab.com/hmailserver/hmailserver","events":[{"introduced":"e4b7163189ac6ce365bb954cf3e264e2e3105a18"},{"fixed":"e3c448aa66fc310b74d076884d54fae951296915"}],"database_specific":{"source":["AFFECTED_FIELD","DESCRIPTION"],"extracted_events":[{"introduced":"6.0.0"},{"fixed":"6.3.6"},{"fixed":"6.3.5"}]}}],"versions":["v6.3.5","v6.3.4","v6.3.3","v6.3.2","build-inputs-1","v6.3.1","v6.3.0","v6.2.28","v6.2.27","v6.2.26","v6.2.25","v6.2.24","v6.2.23-alpha2","v6.2.23-alpha1","v6.2.22-pre6","v6.2.22-pre5","v6.2.22-pre4","v6.2.22-pre3","v6.2.22-pre2","v6.2.22-pre1","v6.2.21","v6.2.20","v6.2.19","v6.2.18","v6.2.17","v6.2.16","v6.2.15","v6.2.14","v6.2.13","v6.2.12","v6.2.11","v6.2.10","v6.2.9","v6.2.8","v6.2.7","v6.2.6","v6.2.5","v6.2.4","v6.2.3","v6.2.2","v6.2.1","v6.2.0","v6.1.0","v6.0.0-B4","v6.0.0-B3","v6.0.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-107581.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}