80 行
6.8 KiB
JSON
80 行
6.8 KiB
JSON
{
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"canonical_id": "traefik--CVE-2026-29054",
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"system_id": "traefik",
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"display_name": "Traefik",
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"category": "servers",
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"advisory_mode": "server",
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"title": "traefik CVE-2024-45410 fix bypass: lowercase `Connection` tokens can delete traefik-managed forwarded identity headers (for example, `X-Real-Ip`)",
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"summary": "## Impact\n\nThere is a potential vulnerability in Traefik managing the `Connection` header with `X-Forwarded` headers.\n\nWhen Traefik processes HTTP/1.1 requests, the protection put in place to prevent the removal of Traefik-managed `X-Forwarded` headers (such as `X-Real-Ip`, `X-Forwarded-Host`, `X-Forwarded-Port`, etc.) via the `Connection` header does not handle case sensitivity correctly. The `Connection` tokens are compared case-sensitively against the protected header names, but the actual header deletion operates case-insensitively. As a result, a remote unauthenticated client can use lowercase `Connection` tokens (e.g. `Connection: x-real-ip`) to bypass the protection and trigger the removal of Traefik-managed forwarded identity headers.\n\nThis is a bypass of the fix for [CVE-2024-45410](https://github.com/traefik/traefik/security/advisories/GHSA-62c8-mh53-4cqv).\n\nDepending on the deployment, the impact may be higher if downstream services rely on these headers (such as `X-Real-Ip` or `X-Forwarded-*`) for authentication, authorization, routing, or scheme decisions.\n\n## Patches\n\n- https://github.com/traefik/traefik/releases/tag/v2.11.38\n- https://github.com/traefik/traefik/releases/tag/v3.6.9\n\n## Workarounds\n\nNo workaround available.\n\n## For more information\n\nIf there are any questions or comments about this advisory, please [open an issue](https://github.com/traefik/traefik/issues).\n\n---\n\n<details>\n<summary>Original Description</summary>\n\nTraefik's XForwarded middleware (removeConnectionHeaders) tries to prevent clients from using the Connection header to strip trusted X-Forwarded-* headers, but the protection compares the Connection tokens case-sensitively while the deletion is case-insensitive.\n\nAs a result, a remote unauthenticated client can send a lowercase token like Connection: x-real-ip and still trigger deletion of traefik-managed X-Real-Ip (and similarly named headers in the managed list).\n\nThis can cause downstream routing, scheme, and header-based authn/authz decisions to be evaluated with missing trusted forwarding identity headers.\n\n### Severity\n\nCRITICAL\n\nRationale: the PoC demonstrates an end-to-end access control bypass pattern when a downstream service uses proxy-provided identity headers (for example, X-Real-Ip) for IP allowlists or trust decisions. A remote unauthenticated client can strip the traefik-managed identity header via a lowercase Connection token, causing the downstream service to evaluate the request without the expected header signal.\n\n### Relevant Links\n\n- Repository: https://github.com/traefik/traefik\n- Pinned commit: a4a91344edcdd6276c1b766ca19ee3f0e346480f\n- Callsite (pinned): https://github.com/traefik/traefik/blob/a4a91344edcdd6276c1b766ca19ee3f0e346480f/pkg/middlewares/forwardedheaders/forwarded_header.go#L225\n\n### Vulnerability Details\n\n#### Root Cause\n\nremoveConnectionHeaders uses a case-sensitive membership check for protected header names when inspecting Connection tokens, but it deletes headers via net/http which treats header names case-insensitively. A lowercase token bypasses the protection check and still triggers deletion.\n\n#### Attacker Control / Attack Path\n\nRemote unauthenticated HTTP client (untrusted IP) sends Connection: x-real-ip, and Traefik deletes the generated X-Real-Ip header.\n\n### Proof of Concept\n\nThe attached poc.zip contains a deterministic, make-based integration PoC with a canonical run and a negative control.\n\nCanonical (vulnerable):\n\n unzip poc.zip -d poc\n cd poc\n make test\n\nOutput contains:\n\n [CALLSITE_HIT]: pkg/middlewares/forwardedheaders/forwarded_header.go:225\n [PROOF_MARKER]: downstream_admin_bypass=1 x_real_ip_present=0\n\nControl (same env, no lowercase token):\n\n unzip poc.zip -d poc\n cd poc\n make test\n\nOutput contains:\n\n [CALLSITE_HIT]: pkg/middlewares/forwardedheaders/forwarded_header.go:225\n [NC_MARKER]: downstream_admin_bypass=0 x_real_ip_present=1\n\nExpected: Connection tokens are handled case-insensitively and protected identity headers (for example, X-Real-Ip and X-Forwarded-*) are not deleted due to client-supplied Connection options (regardless of token casing).\n\nActual: Lowercase Connection tokens bypass the protection check and still trigger deletion of traefik-managed identity headers (for example, X-Real-Ip).\n\n### Recommended Fix\n\n- Case-fold (or otherwise canonicalize) Connection header tokens before comparing them against protected header names.\n- Add a regression test covering lowercase tokens (for example, Connection: x-real-ip).\n\nFix accepted when: a request with Connection: x-real-ip does not cause deletion of traefik-managed X-Real-Ip, and a regression test covers this behavior.\n\n</details>",
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"published_at": "2026-03-04T21:19:08Z",
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"updated_at": "2026-03-05T22:46:31.066201Z",
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"severity": "low",
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"cvss_score": 3.1,
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"exploit_status": "unknown",
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"source_confidence": "official",
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"official_source_url": "https://github.com/traefik/traefik/security/advisories/GHSA-92mv-8f8w-wq52",
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"secondary_source_urls": [
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"https://nvd.nist.gov/vuln/detail/CVE-2026-29054",
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"https://github.com/traefik/traefik",
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"https://github.com/traefik/traefik/releases/tag/v2.11.38",
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"https://github.com/traefik/traefik/releases/tag/v3.6.9"
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],
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"aliases": [
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"CVE-2026-29054",
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"GHSA-92mv-8f8w-wq52"
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],
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"cve_ids": [
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"CVE-2026-29054"
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],
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"ghsa_ids": [
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"GHSA-92mv-8f8w-wq52"
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],
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"osv_ids": [
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"GHSA-92mv-8f8w-wq52"
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],
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"affected_versions": [
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"introduced=2.11.9, fixed<2.11.38",
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"introduced=3.1.3, fixed<3.6.9"
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],
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"fixed_versions": [
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"2.11.38",
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"3.6.9"
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],
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"package_name": "github.com/traefik/traefik/v3",
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"render_markdown": false,
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"case_path": null,
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"secure_code_topics": [
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"proxy-trust-boundary",
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"request-smuggling-boundary",
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"token-cookie-storage",
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"authz-server-side-recheck",
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"dependency-upgrade-policy"
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],
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"status": "generated",
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"triage_reasons": [],
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"verification_status": "triage-manual",
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"verification_mode": "synthetic",
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"last_verified_at": null,
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"last_run_id": null,
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"evidence_bundle": null,
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"historical_status": null,
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"latest_status": null,
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"browser_evidence": {
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"required": false,
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"present": false,
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"refs": []
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},
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"repro_profile_id": "authz-bypass-generic",
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"artifact_mode": "synthetic",
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"blocked_reason": null,
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"metadata": {
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"source_names": [
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"OSV Traefik"
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],
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"source_kinds": [
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"osv-batch"
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],
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"candidate_count": 1
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}
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}
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