BREW-SNAKEMAKE-CVE-2026-44431 (GHSA-QCCP-GFCP-XXVC)
Vulnerability from osv_homebrew – Published: 2026-08-13 17:34 – Updated: 2026-09-17 20:10 – Source websiteImpact
When following cross-origin redirects for requests made using urllib3’s high-level APIs, such as urllib3.request(), PoolManager.request(), and ProxyManager.request(), sensitive headers — Authorization, Cookie, and Proxy-Authorization (defined in Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT) — are stripped by default, as expected.
However, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers.
Affected usage
Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected if they allow cross-origin redirects while making requests through HTTPConnection.urlopen() instances created via ProxyManager.connection_from_url().
Remediation
Upgrade to urllib3 version 2.7.0 or later, in which sensitive headers are stripped from redirects followed by HTTPConnection.
If upgrading is not immediately possible, avoid using this low-level redirect flow for cross-origin redirects. If appropriate for your use case, switch to ProxyManager.request().
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "urllib3",
"resource_purl": "pkg:pypi/urllib3@2.7.0",
"upstream_fixed_in": "2.7.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "snakemake",
"purl": "pkg:brew/snakemake"
},
"ranges": [
{
"events": [
{
"introduced": "5.1.5"
},
{
"fixed": "9.20.0_1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/urllib3@2.7.0",
"name": "urllib3",
"resource": "urllib3",
"strategy": "registry",
"subject_version": "2.7.0"
}
]
},
"details": "### Impact\n\nWhen following cross-origin redirects for requests made using urllib3\u2019s high-level APIs, such as `urllib3.request()`, `PoolManager.request()`, and `ProxyManager.request()`, sensitive headers \u2014 `Authorization`, `Cookie`, and `Proxy-Authorization` (defined in `Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT`) \u2014 are stripped by default, as expected.\n\nHowever, cross-origin redirects followed from the low-level API via `ProxyManager.connection_from_url().urlopen(..., assert_same_host=False)` still forward these sensitive headers.\n\n### Affected usage\n\nApplications and libraries using urllib3 versions earlier than 2.7.0 may be affected if they allow cross-origin redirects while making requests through `HTTPConnection.urlopen()` instances created via `ProxyManager.connection_from_url()`.\n\n### Remediation\n\nUpgrade to urllib3 version 2.7.0 or later, in which sensitive headers are stripped from redirects followed by `HTTPConnection`.\n\nIf upgrading is not immediately possible, avoid using this low-level redirect flow for cross-origin redirects. If appropriate for your use case, switch to `ProxyManager.request()`.",
"id": "BREW-snakemake-CVE-2026-44431",
"modified": "2026-09-17T20:10:37Z",
"published": "2026-08-13T17:34:42Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44431"
},
{
"type": "PACKAGE",
"url": "https://github.com/urllib3/urllib3"
}
],
"schema_version": "1.7.3",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "urllib3: Sensitive headers forwarded across origins in proxied low-level redirects",
"upstream": [
"GHSA-qccp-gfcp-xxvc",
"CVE-2026-44431",
"PYSEC-2026-141"
]
}
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.
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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.