{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-105766", "assignerOrgId": "82cea9a6-e9e3-46fe-bdb0-3673de380178", "state": "PUBLISHED", "assignerShortName": "chainguard", "dateReserved": "2026-10-05T19:21:04.930Z", "datePublished": "2026-10-05T19:45:50.015Z", "dateUpdated": "2026-10-06T13:44:09.303Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "82cea9a6-e9e3-46fe-bdb0-3673de380178", "shortName": "chainguard", "dateUpdated": "2026-10-05T19:45:50.015Z" }, "title": "Chainguard Academy (edu) Nginx directory redirect downgrades HTTPS requests to HTTP", "problemTypes": [ { "descriptions": [ { "lang": "en", "cweId": "CWE-319", "description": "CWE-319 Cleartext Transmission of Sensitive Information", "type": "CWE" } ] } ], "impacts": [ { "capecId": "CAPEC-94", "descriptions": [ { "lang": "en", "value": "CAPEC-94 Adversary in the Middle (AiTM)" } ] } ], "affected": [ { "vendor": "Chainguard", "product": "Chainguard Academy (edu)", "repo": "https://github.com/chainguard-dev/edu", "modules": [ "Nginx trailing-slash directory redirect" ], "versions": [ { "status": "affected", "version": "0b75ff98057f69b044a3e7194e428066ac5ad0d4", "lessThan": "93dc0e50739c225f5aee2e803800a47fc0feb906", "versionType": "git" } ], "defaultStatus": "unaffected", "programFiles": [ "nginx.conf" ] } ], "descriptions": [ { "lang": "en", "value": "Use of the backend-facing $scheme variable in the trailing-slash directory redirect in nginx.conf of Chainguard Academy (edu) from commit 0b75ff98057f69b044a3e7194e428066ac5ad0d4 before commit 93dc0e50739c225f5aee2e803800a47fc0feb906 allows an on-path network attacker to read or modify documentation content served to a victim via an HTTPS request for a slashless directory path, because TLS terminates at the load balancer in front of Nginx and the resulting 301 response redirects the client to a plaintext http:// URL. Browsers that ship the HSTS preload list are not affected, because the .dev top-level domain is preloaded; clients that do not enforce HSTS, such as command-line HTTP clients and scripts that follow redirects, are affected.", "supportingMedia": [ { "type": "text/html", "base64": false, "value": "

Use of the backend-facing $scheme variable in the trailing-slash directory redirect in nginx.conf of Chainguard Academy (edu) from commit 0b75ff98057f69b044a3e7194e428066ac5ad0d4 before commit 93dc0e50739c225f5aee2e803800a47fc0feb906 allows an on-path network attacker to read or modify documentation content served to a victim via an HTTPS request for a slashless directory path, because TLS terminates at the load balancer in front of Nginx and the resulting 301 response redirects the client to a plaintext http:// URL. Browsers that ship the HSTS preload list are not affected, because the .dev top-level domain is preloaded; clients that do not enforce HSTS, such as command-line HTTP clients and scripts that follow redirects, are affected.

" } ] } ], "references": [ { "url": "https://github.com/chainguard-dev/edu/commit/93dc0e50739c225f5aee2e803800a47fc0feb906", "name": "Fix commit 93dc0e5", "tags": [ "patch" ] }, { "url": "https://github.com/chainguard-dev/edu/pull/3989", "name": "chainguard-dev/edu#3989", "tags": [ "patch" ] } ], "metrics": [ { "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ], "cvssV4_0": { "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "PASSIVE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "LOW", "baseScore": 2.3, "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N" } }, { "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ], "cvssV3_1": { "version": "3.1", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE", "baseSeverity": "LOW", "baseScore": 3.1, "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N" } } ], "source": { "discovery": "INTERNAL" }, "x_generator": { "engine": "Vulnogram 1.0.5" }, "datePublic": "2026-09-11T16:16:00.000Z", "tags": [ "exclusively-hosted-service" ], "configurations": [ { "lang": "en", "value": "TLS is terminated before requests reach Nginx (as in the production Cloud Run deployment), and the client following the redirect does not enforce HSTS for edu.chainguard.dev.", "supportingMedia": [ { "type": "text/html", "base64": false, "value": "

TLS is terminated before requests reach Nginx (as in the production Cloud Run deployment), and the client following the redirect does not enforce HSTS for edu.chainguard.dev.

" } ] } ], "solutions": [ { "lang": "en", "value": "Fixed in commit 93dc0e50739c225f5aee2e803800a47fc0feb906, which hardcodes the https scheme in the redirect. The fix is deployed to edu.chainguard.dev; no user action is required.", "supportingMedia": [ { "type": "text/html", "base64": false, "value": "

Fixed in commit 93dc0e50739c225f5aee2e803800a47fc0feb906, which hardcodes the https scheme in the redirect. The fix is deployed to edu.chainguard.dev; no user action is required.

" } ] } ], "timeline": [ { "time": "2025-07-14T21:34:00.000Z", "lang": "en", "value": "Vulnerable redirect introduced (chainguard-dev/edu#2411)" }, { "time": "2026-09-11T16:16:00.000Z", "lang": "en", "value": "Fix merged (chainguard-dev/edu#3989)" } ], "credits": [ { "lang": "en", "value": "Matthew Helmke (https://github.com/matthewhelmke)", "type": "remediation developer" }, { "lang": "en", "value": "SunnyR (https://github.com/SunnyR)", "type": "coordinator" }, { "lang": "en", "value": "Chainguard (https://chainguard.dev)", "type": "coordinator" } ] }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-10-06T13:43:50.196822Z", "id": "CVE-2026-105766", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-06T13:44:09.303Z" } } ] } }