Vulnerabilities in pkg:pypi/httpx2

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8xx6-hgc6-gc2m",
  "modified" : "2026-09-08T20:48:59Z",
  "published" : "2026-09-08T20:48:59Z",
  "aliases" : [ "CVE-2026-84382" ],
  "summary" : "HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)",
  "details" : "### Summary\n\nWhen decoding a compressed response body (`gzip`, `deflate`, `br`, or `zstd`), HTTPX2 fully decompressed each network read before yielding content to the application. A small compressed input could therefore cause a large intermediate memory allocation, even when the application streamed the response to keep memory usage bounded.\n\n### Details\n\nHTTPX2's default transport reads the socket in pieces of up to 64 KiB. Before `2.12.0`, each piece was inflated completely into one intermediate allocation before any decompressed bytes were yielded.\n\nAt DEFLATE's maximum compression ratio of roughly 1032:1, a 64 KiB compressed chunk can expand to about 64 MiB in one allocation. Brotli and Zstandard responses can cause similarly large amplification. Streaming the response did not prevent these transient allocations.\n\n### Impact\n\nApplications that fetch resources from untrusted or attacker-influenced servers - such as webhook receivers, link unfurlers, crawlers, SSRF-reachable fetchers, and redirect followers - can experience memory pressure or out-of-memory termination when processing a malicious compressed response. No authentication or user interaction is required beyond issuing a request to the server.\n\n### Mitigation\n\nUpgrade to HTTPX2 `2.12.0` or later. Patched versions decompress responses incrementally with bounded intermediate buffers, including responses with multiple content encodings.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "httpx2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.12.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/pydantic/httpx2/security/advisories/GHSA-8xx6-hgc6-gc2m"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-84382"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pydantic/httpx2/pull/1126"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pydantic/httpx2/commit/4fd0c70a3f207c618b145934792f791bccfb39f8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/pydantic/httpx2"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pydantic/httpx2/releases/tag/v2.12.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-409" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-08T20:48:59Z",
    "nvd_published_at" : "2026-09-02T19:18:08Z"
  }
}