{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-18355","assignerOrgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","state":"PUBLISHED","assignerShortName":"redhat","dateReserved":"2026-07-30T07:37:32.170Z","datePublished":"2026-09-07T14:14:43.759Z","dateUpdated":"2026-09-08T21:58:57.884Z"},"containers":{"cna":{"title":"389-ds-base: 389-ds-base: heap buffer overflow via sasl wrapped-record length lower-bound underflow in sasl_io_start_packet()","metrics":[{"other":{"content":{"value":"Important","namespace":"https://access.redhat.com/security/updates/classification/"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"format":"CVSS"}],"descriptions":[{"lang":"en","value":"A heap buffer overflow flaw was found in the SASL I/O layer of 389 Directory Server (389-ds-base). In sasl_io_start_packet(), the wrapped-record length read from the wire is validated only against an upper bound. A small wire length (0, 1, or 2) produces an encrypted_buffer_count below the already-consumed encrypted_buffer_offset, causing an unsigned subtraction underflow in sasl_io_read_packet(). PR_Recv is then requested to read approximately 4 GiB into a 1024-byte heap buffer, resulting in a heap buffer overflow with attacker-controlled content. After a successful SASL bind with integrity protection (SSF > 0), a remote authenticated attacker can cause a denial of service or potentially achieve remote code execution. This flaw is distinct from CVE-2026-11774, whose fix only guards against upper-bound overflow."}],"affected":[{"vendor":"Red Hat","product":"Red Hat Directory Server 11.7 E4S for RHEL 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"redhat-ds:11","defaultStatus":"affected","versions":[{"version":"8080020260903102346.f969626e","lessThan":"*","versionType":"rpm","status":"unaffected"}],"cpes":["cpe:/a:redhat:directory_server_e4s:11.7::el8"]},{"vendor":"Red Hat","product":"Red Hat Directory Server 11.9 for RHEL 8","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"redhat-ds:11","defaultStatus":"affected","versions":[{"version":"8100020260904171440.37ed7c03","lessThan":"*","versionType":"rpm","status":"unaffected"}],"cpes":["cpe:/a:redhat:directory_server:11.9::el8"]},{"vendor":"Red Hat","product":"Red Hat Directory Server 12.2 E4S for RHEL 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Underflow (Wrap or Wraparound)","lang":"en","type":"CWE"}]}],"x_redhatCweChain":"CWE-191: Integer Underflow (Wrap or Wraparound)","workarounds":[{"lang":"en","value":"Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible."}],"timeline":[{"lang":"en","time":"2026-07-08T00:00:00.000Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-09-07T09:00:00.000Z","value":"Made public."}],"credits":[{"lang":"en","value":"Red Hat would like to thank Adam Korczynski (Ada Logics), Arthur Chan (Ada Logics), David Korczynski (Ada Logics), and Team (Anthropic) for reporting this issue."}],"providerMetadata":{"orgId":"53f830b8-0a3f-465b-8143-3b8a9948e749","shortName":"redhat","dateUpdated":"2026-09-08T21:58:57.884Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-08T16:40:59.242163Z","id":"CVE-2026-18355","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-08T16:54:53.347Z"}}]}}