Vulnerability-Lookup

GHSA-FQWV-PCM9-9M42

Vulnerability from github – Published: 2026-10-20 03:32 – Updated: 2026-10-20 03:32

Details

Summary

Before version 0.9.0, Pingora accepted HTTP/2 requests whose Host header differed from the :authority pseudo-header. Request filters, cache keys, and logs that read the request URI (session.req_header().uri) saw the :authority value, but the upstream received the client-supplied Host value. Pingora also accepted :authority values containing userinfo (for example, user@example.com). This violates RFC 9113 Section 8.3.1, which requires an intermediary to use the :authority value for Host and replace any existing Host field.

Root cause

HTTP/2 to HTTP/1.1: Host was generated from :authority only when the request had no Host header, so a conflicting client Host was forwarded unchanged.

HTTP/2 to HTTP/2: the client Host header was removed and used to overwrite the upstream :authority, after request filters had already run against the original :authority.

The HTTP/2 server did not compare Host with :authority and did not reject userinfo in the authority.

Impact

A remote, unauthenticated attacker can send a single HTTP/2 request that the application sees as one host and the upstream receives as another. Where request filters, access controls, or cache keys use the URI authority and the upstream routes by Host, this can lead to:

Cache poisoning: a response from another virtual host is stored under the victim host's cache key and served to other users (this also requires the upstream to serve different content per Host).

Host-based access control bypass: a request approved for one host is served by a different virtual host on the upstream.

Deployments that do not accept HTTP/2 from clients, or that do not use the request authority for security or caching decisions, are not affected.

Note that Cloudflare CDN customers were unaffected, as internal Pingora services at Cloudflare do not have HTTP/2 clients.

Mitigation:

Upgrade to pingora 0.9.0 or later. Pingora now returns 400 Bad Request for HTTP/2 requests whose Host differs from :authority, that contain more than one Host, or whose authority contains userinfo, and keeps the upstream Host or :authority consistent with the request authority. Fix commits: https://github.com/cloudflare/pingora/commit/915590a91811877795531f6ba0927a3138b5cb4b , https://github.com/cloudflare/pingora/commit/ffab8302d08d4292d1924eb8fe84647fd5cb8e76

If you cannot upgrade: in request_filter, reject HTTP/2 requests that carry a Host header different from the URI authority, or whose authority contains '@'.

Severity

6.3 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-105298"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-20T01:17:09Z",
    "severity": "MODERATE"
  },
  "details": "Summary\n\n\n\nBefore version 0.9.0, Pingora accepted HTTP/2 requests whose Host header differed from the :authority pseudo-header. Request filters, cache keys, and logs that read the request URI (session.req_header().uri) saw the :authority value, but the upstream received the client-supplied Host value. Pingora also accepted :authority values containing userinfo (for example, user@example.com). This violates RFC 9113 Section 8.3.1, which requires an intermediary to use the :authority value for Host and replace any existing Host field.\n\n\n\n\nRoot cause\n\n  *  \n\nHTTP/2 to HTTP/1.1: Host was generated from :authority only when the request had no Host header, so a conflicting client Host was forwarded unchanged.\n\n\n  *  \n\nHTTP/2 to HTTP/2: the client Host header was removed and used to overwrite the upstream :authority, after request filters had already run against the original :authority.\n\n\n  *  \n\nThe HTTP/2 server did not compare Host with :authority and did not reject userinfo in the authority.\n\n\n\n\n\n\n\nImpact\n\n\n\nA remote, unauthenticated attacker can send a single HTTP/2 request that the application sees as one host and the upstream receives as another. Where request filters, access controls, or cache keys use the URI authority and the upstream routes by Host, this can lead to:\n\n  *  \n\nCache poisoning: a response from another virtual host is stored under the victim host\u0027s cache key and served to other users (this also requires the upstream to serve different content per Host).\n\n\n  *  \n\nHost-based access control bypass: a request approved for one host is served by a different virtual host on the upstream.\n\n\n\n\n\n\nDeployments that do not accept HTTP/2 from clients, or that do not use the request authority for security or caching decisions, are not affected.\n\n\n\n\nNote that Cloudflare CDN customers were unaffected, as internal Pingora services at Cloudflare do not have HTTP/2 clients.\n\n\n\n\nMitigation:\n\n  *  \n\nUpgrade to pingora 0.9.0 or later. Pingora now returns 400 Bad Request for HTTP/2 requests whose Host differs from :authority, that contain more than one Host, or whose authority contains userinfo, and keeps the upstream Host or :authority consistent with the request authority. Fix commits:  https://github.com/cloudflare/pingora/commit/915590a91811877795531f6ba0927a3138b5cb4b ,  https://github.com/cloudflare/pingora/commit/ffab8302d08d4292d1924eb8fe84647fd5cb8e76 \n\n\n  *  \n\nIf you cannot upgrade: in request_filter, reject HTTP/2 requests that carry a Host header different from the URI authority, or whose authority contains \u0027@\u0027.",
  "id": "GHSA-fqwv-pcm9-9m42",
  "modified": "2026-10-20T03:32:43Z",
  "published": "2026-10-20T03:32:43Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105298"
    },
    {
      "type": "WEB",
      "url": "https://github.com/cloudflare/pingora"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-105298 (GCVE-0-2026-105298)

Vulnerability from cvelistv5 – Published: 2026-10-20 00:46 – Updated: 2026-10-20 00:46

Title

Pingora HTTP/2 :authority and Host header mismatch enables cache poisoning and host-based access control bypass

Summary

Summary Before version 0.9.0, Pingora accepted HTTP/2 requests whose Host header differed from the :authority pseudo-header. Request filters, cache keys, and logs that read the request URI (session.req_header().uri) saw the :authority value, but the upstream received the client-supplied Host value. Pingora also accepted :authority values containing userinfo (for example, user@example.com). This violates RFC 9113 Section 8.3.1, which requires an intermediary to use the :authority value for Host and replace any existing Host field. Root cause * HTTP/2 to HTTP/1.1: Host was generated from :authority only when the request had no Host header, so a conflicting client Host was forwarded unchanged. * HTTP/2 to HTTP/2: the client Host header was removed and used to overwrite the upstream :authority, after request filters had already run against the original :authority. * The HTTP/2 server did not compare Host with :authority and did not reject userinfo in the authority. Impact A remote, unauthenticated attacker can send a single HTTP/2 request that the application sees as one host and the upstream receives as another. Where request filters, access controls, or cache keys use the URI authority and the upstream routes by Host, this can lead to: * Cache poisoning: a response from another virtual host is stored under the victim host's cache key and served to other users (this also requires the upstream to serve different content per Host). * Host-based access control bypass: a request approved for one host is served by a different virtual host on the upstream. Deployments that do not accept HTTP/2 from clients, or that do not use the request authority for security or caching decisions, are not affected. Note that Cloudflare CDN customers were unaffected, as internal Pingora services at Cloudflare do not have HTTP/2 clients. Mitigation: * Upgrade to pingora 0.9.0 or later. Pingora now returns 400 Bad Request for HTTP/2 requests whose Host differs from :authority, that contain more than one Host, or whose authority contains userinfo, and keeps the upstream Host or :authority consistent with the request authority. Fix commits: https://github.com/cloudflare/pingora/commit/915590a91811877795531f6ba0927a3138b5cb4b , https://github.com/cloudflare/pingora/commit/ffab8302d08d4292d1924eb8fe84647fd5cb8e76 * If you cannot upgrade: in request_filter, reject HTTP/2 requests that carry a Host header different from the URI authority, or whose authority contains '@'.

Severity

6.3 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Assigner

cloudflare CNA under the mitre root

CNA scorecard – unranked: 8 records in the last 180 days, 10 needed details

References

1 reference

URL	Tags
https://github.com/cloudflare/pingora

Impacted products

1 product

Vendor	Product	Version
Cloudflare	https://github.com/cloudflare/pingora	Affected: 0.1.0 , < 0.9.0 (semver)

Credits

Reported by bipol4r (GitHub)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "https://github.com/cloudflare/pingora",
          "repo": "https://github.com/cloudflare/pingora",
          "vendor": "Cloudflare",
          "versions": [
            {
              "lessThan": "0.9.0",
              "status": "affected",
              "version": "0.1.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Reported by bipol4r (GitHub)"
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              "value": "\u003cp\u003eSummary\u003c/p\u003e\u003cp\u003eBefore version 0.9.0, Pingora accepted HTTP/2 requests whose Host header differed from the :authority pseudo-header. Request filters, cache keys, and logs that read the request URI (session.req_header().uri) saw the :authority value, but the upstream received the client-supplied Host value. Pingora also accepted :authority values containing userinfo (for example, user@example.com). This violates RFC 9113 Section 8.3.1, which requires an intermediary to use the :authority value for Host and replace any existing Host field.\u003c/p\u003e\u003cbr\u003e\u003cp\u003eRoot cause\u003c/p\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eHTTP/2 to HTTP/1.1: Host was generated from :authority only when the request had no Host header, so a conflicting client Host was forwarded unchanged.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHTTP/2 to HTTP/2: the client Host header was removed and used to overwrite the upstream :authority, after request filters had already run against the original :authority.\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eThe HTTP/2 server did not compare Host with :authority and did not reject userinfo in the authority.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003cbr\u003e\u003cp\u003eImpact\u003c/p\u003e\u003cp\u003eA remote, unauthenticated attacker can send a single HTTP/2 request that the application sees as one host and the upstream receives as another. Where request filters, access controls, or cache keys use the URI authority and the upstream routes by Host, this can lead to:\u003c/p\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eCache poisoning: a response from another virtual host is stored under the victim host\u0027s cache key and served to other users (this also requires the upstream to serve different content per Host).\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eHost-based access control bypass: a request approved for one host is served by a different virtual host on the upstream.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003cp\u003eDeployments that do not accept HTTP/2 from clients, or that do not use the request authority for security or caching decisions, are not affected.\u003c/p\u003e\u003cbr\u003e\u003cp\u003eNote that Cloudflare CDN customers were unaffected, as internal Pingora services at Cloudflare do not have HTTP/2 clients.\u003c/p\u003e\u003cbr\u003e\u003cdiv\u003e\u003cp\u003eMitigation:\u003c/p\u003e\u003cul\u003e\u003cli\u003e\u003cp\u003eUpgrade to pingora 0.9.0 or later. Pingora now returns 400 Bad Request for HTTP/2 requests whose Host differs from :authority, that contain more than one Host, or whose authority contains userinfo, and keeps the upstream Host or :authority consistent with the request authority. Fix commits: \u003ca href=\"https://github.com/cloudflare/pingora/commit/915590a91811877795531f6ba0927a3138b5cb4b\"\u003ehttps://github.com/cloudflare/pingora/commit/915590a91811877795531f6ba0927a3138b5cb4b\u003c/a\u003e, \u003ca href=\"https://github.com/cloudflare/pingora/commit/ffab8302d08d4292d1924eb8fe84647fd5cb8e76\"\u003ehttps://github.com/cloudflare/pingora/commit/ffab8302d08d4292d1924eb8fe84647fd5cb8e76\u003c/a\u003e\u003c/p\u003e\u003c/li\u003e\u003cli\u003e\u003cp\u003eIf you cannot upgrade: in request_filter, reject HTTP/2 requests that carry a Host header different from the URI authority, or whose authority contains \u0027@\u0027.\u003c/p\u003e\u003c/li\u003e\u003c/ul\u003e\u003c/div\u003e"
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            "attackVector": "NETWORK",
            "baseScore": 6.3,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
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            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
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            "vulnAvailabilityImpact": "NONE",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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    "datePublished": "2026-10-20T00:46:21.902Z",
    "dateReserved": "2026-10-05T04:18:59.291Z",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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