CVE-2026-66357

httpd has never implemented obs-fold (RFC 2616 §2.2 / RFC 7230 §3.2.4 header continuation lines). Every CRLF followed by a non-CRLF octet unconditionally starts a new header. This missing feature became a security concern as the understanding of HTTP request smuggling attacks evolved. This issue affects OTP from OTP 17.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP 17.0, corresponding to inets before 5.10, is affected is unknown.

CVSS

No CVSS.

References

Link	Resource
https://cna.erlef.org/cves/CVE-2026-66357.html
https://github.com/erlang/otp/commit/220d618d2479a7180b4a06d0c5aacfaa4af4a85b
https://github.com/erlang/otp/commit/273d8958de38ff2a7fe0c5dcc5b6bfe6f65717f3
https://github.com/erlang/otp/commit/e640d599287d2eba919e6f13b91f042d7dbe6ff4
https://github.com/erlang/otp/security/advisories/GHSA-qh2f-33hj-37qf
https://osv.dev/vulnerability/EEF-CVE-2026-66357

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-01 15:17

Updated : 2026-09-08 01:17

NVD link : CVE-2026-66357

Mitre link : CVE-2026-66357

CVE.ORG link : CVE-2026-66357

JSON object : View

Products Affected

No product.

CWE

CWE-444

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

{"id": "CVE-2026-66357", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-66357", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-01T15:56:00.806246Z"}}], "cvssMetricV40": [{"type": "Secondary", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "LOW", "vulnIntegrityImpact": "HIGH", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "affectedData": [{"cpes": ["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"], "vendor": "Erlang", "product": "OTP", "versions": [{"status": "unknown", "version": "0", "lessThan": "17.0", "versionType": "otp"}, {"status": "affected", "version": "17.0", "lessThan": "27.3.4.17", "versionType": "otp"}, {"status": "affected", "version": "28.0", "lessThan": "28.5.0.6", "versionType": "otp"}, {"status": "affected", "version": "29.0", "lessThan": "29.0.6", "versionType": "otp"}], "packageURL": "pkg:software-id/erlang.org/otp", "packageName": "otp", "defaultStatus": "unaffected"}, {"cpes": ["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"], "repo": "https://github.com/erlang/otp", "vendor": "Erlang", "product": "OTP", "versions": [{"status": "unknown", "version": "0", "lessThan": "5.10", "versionType": "otp"}, {"status": "affected", "version": "5.10", "lessThan": "9.3.2.7", "versionType": "otp"}, {"status": "affected", "version": "9.4", "lessThan": "9.6.2.3", "versionType": "otp"}, {"status": "affected", "version": "9.7", "lessThan": "9.7.2", "versionType": "otp"}], "packageURL": "pkg:otp/inets", "packageName": "inets", "defaultStatus": "unaffected"}, {"cpes": ["cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"], "repo": "https://github.com/erlang/otp", "vendor": "Erlang", "product": "OTP", "versions": [{"status": "affected", "changes": [{"at": "220d618d2479a7180b4a06d0c5aacfaa4af4a85b", "status": "unaffected"}, {"at": "273d8958de38ff2a7fe0c5dcc5b6bfe6f65717f3", "status": "unaffected"}, {"at": "e640d599287d2eba919e6f13b91f042d7dbe6ff4", "status": "unaffected"}], "version": "84adefa331c4159d432d22840663c38f155cd4c1", "lessThan": "*", "versionType": "git"}], "packageURL": "pkg:github/erlang/otp", "packageName": "erlang/otp", "collectionURL": "https://github.com", "defaultStatus": "unaffected"}]}], "published": "2026-09-01T15:17:23.047", "references": [{"url": "https://cna.erlef.org/cves/CVE-2026-66357.html", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/erlang/otp/commit/220d618d2479a7180b4a06d0c5aacfaa4af4a85b", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/erlang/otp/commit/273d8958de38ff2a7fe0c5dcc5b6bfe6f65717f3", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/erlang/otp/commit/e640d599287d2eba919e6f13b91f042d7dbe6ff4", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://github.com/erlang/otp/security/advisories/GHSA-qh2f-33hj-37qf", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}, {"url": "https://osv.dev/vulnerability/EEF-CVE-2026-66357", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "description": [{"lang": "en", "value": "CWE-444"}]}], "descriptions": [{"lang": "en", "value": "httpd has never implemented obs-fold (RFC 2616 \u00a72.2 / RFC 7230 \u00a73.2.4 header continuation lines). Every CRLF followed by a non-CRLF octet unconditionally starts a new header. This missing feature became a security concern as the understanding of HTTP request smuggling attacks evolved.\n\nThis issue affects OTP from OTP\u00a017.0 before OTP\u00a027.3.4.17, from OTP\u00a028.0 before OTP\u00a028.5.0.6, and from OTP\u00a029.0 before OTP\u00a029.0.6, corresponding to inets from 5.10 before 9.3.2.7, from 9.4 before 9.6.2.3, and from 9.7 before 9.7.2. Whether OTP before OTP\u00a017.0, corresponding to inets before 5.10, is affected is unknown."}], "lastModified": "2026-09-08T01:17:51.840", "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}