OESA-2026-2815 (CVE-2026-9375)
Vulnerability from osv_openeuler – Published: 2026-07-06 11:11 – Updated: 2026-08-06 11:11 – Source websiteHTTP library with thread-safe connection pooling, file post support, sanity friendly, and more.
Security Fix(es):
urllib3 version 2.6.3 is vulnerable to a decompression bomb bypass in its streaming API (preload_content=False) when using Brotli support. The issue arises due to three independent code paths in response.py that bypass the max_length protection introduced in version 2.6.0 to mitigate CVE-2025-66471. Specifically, negative max_length values can be produced due to buffer arithmetic in read(), flush_decoder unconditionally overrides max_length to -1, and _flush_decoder() passes no limit at all, defaulting to unlimited decompression. This allows a malicious HTTP server to trigger an out-of-memory (OOM) condition by decompressing large payloads into memory, leading to a denial of service (DoS). The vulnerability affects urllib3 2.6.3 and Brotli 1.2.0 and impacts applications and libraries using requests or urllib3 to stream content from untrusted sources.(CVE-2026-9375)
| URL | Type | |
|---|---|---|
{
"affected": [
{
"ecosystem_specific": {
"noarch": [
"python3-urllib3-1.26.18-9.oe2403sp1.noarch.rpm"
],
"src": [
"python-urllib3-1.26.18-9.oe2403sp1.src.rpm"
]
},
"package": {
"ecosystem": "openEuler:24.03-LTS-SP1",
"name": "python-urllib3",
"purl": "pkg:rpm/openEuler/python-urllib3\u0026distro=openEuler-24.03-LTS-SP1"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.26.18-9.oe2403sp1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"severity": "High"
},
"details": "HTTP library with thread-safe connection pooling, file post support, sanity friendly, and more.\r\n\r\nSecurity Fix(es):\n\nurllib3 version 2.6.3 is vulnerable to a decompression bomb bypass in its streaming API (`preload_content=False`) when using Brotli support. The issue arises due to three independent code paths in `response.py` that bypass the `max_length` protection introduced in version 2.6.0 to mitigate CVE-2025-66471. Specifically, negative `max_length` values can be produced due to buffer arithmetic in `read()`, `flush_decoder` unconditionally overrides `max_length` to `-1`, and `_flush_decoder()` passes no limit at all, defaulting to unlimited decompression. This allows a malicious HTTP server to trigger an out-of-memory (OOM) condition by decompressing large payloads into memory, leading to a denial of service (DoS). The vulnerability affects urllib3 2.6.3 and Brotli 1.2.0 and impacts applications and libraries using `requests` or `urllib3` to stream content from untrusted sources.(CVE-2026-9375)",
"id": "OESA-2026-2815",
"modified": "2026-08-06T11:11:44Z",
"published": "2026-07-06T11:11:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-2815"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-9375"
}
],
"schema_version": "1.7.2",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "python-urllib3 security update",
"upstream": [
"CVE-2026-9375"
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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