GHSA-gm62-xv2j-4w53
Suggest an improvement- Source
- https://github.com/advisories/GHSA-gm62-xv2j-4w53
- Import Source
- https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/12/GHSA-gm62-xv2j-4w53/GHSA-gm62-xv2j-4w53.json
- JSON Data
- https://api.osv.dev/v1/vulns/GHSA-gm62-xv2j-4w53
- Aliases
- Downstream
- Published
- 2025-12-05T18:15:19Z
- Modified
- 2025-12-05T18:52:50.341818Z
- Severity
-
- 8.9 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H CVSS Calculator
- Summary
- urllib3 allows an unbounded number of links in the decompression chain
- Details
-
Impact
urllib3 supports chained HTTP encoding algorithms for response content according to RFC 9110 (e.g.,
Content-Encoding: gzip, zstd).However, the number of links in the decompression chain was unbounded allowing a malicious server to insert a virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation for the decompressed data.
Affected usages
Applications and libraries using urllib3 version 2.5.0 and earlier for HTTP requests to untrusted sources unless they disable content decoding explicitly.
Remediation
Upgrade to at least urllib3 v2.6.0 in which the library limits the number of links to 5.
If upgrading is not immediately possible, use <code>preload_content=False</code> and ensure that
resp.headers["content-encoding"]contains a safe number of encodings before reading the response content. - Database specific
{ "severity": "HIGH", "github_reviewed": true, "cwe_ids": [ "CWE-770" ], "github_reviewed_at": "2025-12-05T18:15:19Z", "nvd_published_at": "2025-12-05T16:15:51Z" }- References
Affected packages
PyPI / urllib3
Package
- Name
- urllib3
- View open source insights on deps.dev
- Purl
- pkg:pypi/urllib3