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CVE-2026-67194

Courier IMAP before 6.0.1 and Courier Mail Server before 2.0.2 allow authenticated IMAP users to crash the imapd process via deeply nested parenthesized SEARCH queries. The SEARCH command parser (alloc_search_key in searchinfo.C) recursively descends on nested parenthesized groups through a mutual recursion chain with alloc_search_andlist() and alloc_search_notkey(), with no depth limit. Courier IMAP has no overall command line length limit, making exploitation trivial. A single IMAP command wit
Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:da2daa9b9b29bb7ccbf272cf83f8226a80a9be84226bfea07f2770fa122844cb
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
2

Preserved source conflicts

No provider value was silently selected as the winner.

affected · 2 assertions

{"defaultStatus":"affected","packageURL":"pkg:github/svarshavchik/courier","product":"Courier IMAP","repo":"https://github.com/svarshavchik/courier","vendor":"svarshavchik","versions":[{"lessThan":"6.0.1","status":"affected","version":"0","versionType":"semver"}]}

  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/affected/0

{"defaultStatus":"affected","packageURL":"pkg:github/svarshavchik/courier","product":"Courier Mail Server","repo":"https://github.com/svarshavchik/courier","vendor":"svarshavchik","versions":[{"lessThan":"2.0.2","status":"affected","version":"0","versionType":"semver"}]}

  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/affected/1
cvss · 2 assertions

{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":7.1,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"N…

  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/metrics/0/cvssV4_0

{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"metric_type":"cvssV3_1"}

  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/metrics/1/cvssV3_1

Affected products and versions

2 source assertions
{"defaultStatus":"affected","packageURL":"pkg:github/svarshavchik/courier","product":"Courier IMAP","repo":"https://github.com/svarshavchik/courier","vendor":"svarshavchik","versions":[{"lessThan":"6.0.1","status":"affected","version":"0","versionType":"semver"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/affected/0
{"defaultStatus":"affected","packageURL":"pkg:github/svarshavchik/courier","product":"Courier Mail Server","repo":"https://github.com/svarshavchik/courier","vendor":"svarshavchik","versions":[{"lessThan":"2.0.2","status":"affected","version":"0","versionType":"semver"}]}
  • cve_program_cvelist_v5affected
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/affected/1

Provider-owned CVSS observations

2 source assertions
{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":7.1,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"N…
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/metrics/0/cvssV4_0
{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"metric_type":"cvssV3_1"}
  • cve_program_cvelist_v5cvss
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/metrics/1/cvssV3_1

CWE assertions

1 source assertion
{"cweId":"CWE-674","description":"Uncontrolled Recursion","lang":"en","type":"CWE"}
  • cve_program_cvelist_v5cwe
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/problemTypes/0/descriptions/0

Source references

5 source assertions
{"name":"Patch Commit","tags":["patch"],"url":"https://github.com/svarshavchik/courier-libs/commit/b5b5581aabea3efadf5e2944947ff0214aa3533e"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/references/2
{"name":"Courier Mail Server Release Notes","tags":["release-notes"],"url":"https://github.com/svarshavchik/courier/releases/tag/courier%2F2.0.2%2F20260627214309"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/references/1
{"name":"Courier IMAP Release Notes","tags":["release-notes"],"url":"https://github.com/svarshavchik/courier/releases/tag/courier-imap%2F6.0.1%2F20260627214444"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/references/0
{"name":"Debian Package","tags":["product"],"url":"https://packages.debian.org/sid/courier-imap"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/references/3
{"tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/courier-imap-mail-server-stack-overflow-dos-via-nested-search-queries"}
  • cve_program_cvelist_v5reference
    urn:baitaphish:normalized-source-record:v2:0a1a20ec1f0b3e52cc5de7b3a1c676bece6f3212ae2964c46b8a8e213dc381b5 · sha256:4064ad09576fbcdb… · /containers/cna/references/4

Attribution and limitations

  • CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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