CVE-2026-44432
urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API
HIGH 8.9
At a glance
- Source
- NVD
- EPSS
- EPSS 0.68 % · percentile 52 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
Description
urllib3 is an HTTP client library for Python. From 2.6.0 to before 2.7.0, urllib3 could decompress the whole response instead of the requested portion (1) during the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library or (2) when HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here). These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data) on the client side. This vulnerability is fixed in 2.7.0.
Weaknesses (CWE)
- CWE-409 — Improper Handling of Highly Compressed Data (Data Amplification)
References
- https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j
- https://access.redhat.com/security/cve/CVE-2026-44432
- https://bugzilla.redhat.com/show_bug.cgi?id=2477154
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44432.json
- https://access.redhat.com/errata/RHSA-2026:42078
- https://access.redhat.com/errata/RHSA-2026:34160
- https://access.redhat.com/errata/RHSA-2026:42079
- https://access.redhat.com/errata/RHSA-2026:27929
- https://access.redhat.com/errata/RHSA-2026:32992
- https://access.redhat.com/errata/RHSA-2026:28159
- https://access.redhat.com/errata/RHSA-2026:28157
- https://access.redhat.com/errata/RHSA-2026:28000
- https://access.redhat.com/errata/RHSA-2026:60362
- https://access.redhat.com/errata/RHSA-2026:60371
- https://access.redhat.com/errata/RHSA-2026:59409
- https://access.redhat.com/errata/RHSA-2026:28158
- https://access.redhat.com/errata/RHSA-2026:30078
- https://access.redhat.com/errata/RHSA-2026:30089
- https://access.redhat.com/errata/RHSA-2026:30088
- https://access.redhat.com/errata/RHSA-2026:30087
- https://access.redhat.com/errata/RHSA-2026:24542
- https://access.redhat.com/errata/RHSA-2026:24540
- https://access.redhat.com/errata/RHSA-2026:24544
- https://access.redhat.com/errata/RHSA-2026:24541
- https://access.redhat.com/errata/RHSA-2026:42144
- https://access.redhat.com/errata/RHSA-2026:42132
- https://access.redhat.com/errata/RHSA-2026:34374
- https://access.redhat.com/errata/RHSA-2026:25928
- https://access.redhat.com/errata/RHSA-2026:20338
- https://access.redhat.com/errata/RHSA-2026:33313
- https://access.redhat.com/errata/RHSA-2026:25039
- https://access.redhat.com/errata/RHSA-2026:7634
- https://access.redhat.com/errata/RHSA-2026:24069
- https://access.redhat.com/errata/RHSA-2026:25143
- https://access.redhat.com/errata/RHSA-2026:24014
- https://access.redhat.com/errata/RHSA-2026:24374
- https://access.redhat.com/errata/RHSA-2026:7625
- https://access.redhat.com/errata/RHSA-2026:24000
- https://access.redhat.com/errata/RHSA-2026:24009
- https://access.redhat.com/errata/RHSA-2026:22934
- https://access.redhat.com/errata/RHSA-2026:15862
- https://access.redhat.com/errata/RHSA-2026:56347
- https://access.redhat.com/errata/RHSA-2026:43038
- https://access.redhat.com/errata/RHSA-2026:42644
- https://access.redhat.com/errata/RHSA-2026:37275
- https://access.redhat.com/errata/RHSA-2026:33683
- https://access.redhat.com/errata/RHSA-2026:30076
- https://access.redhat.com/errata/RHSA-2026:42796
- https://access.redhat.com/errata/RHSA-2026:41066
- https://access.redhat.com/errata/RHSA-2026:28571
- +12 more
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | HIGH 8.9 | 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 | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat-SADP |
| CVSS 4.0 | HIGH 8.9 | 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/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 | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-mf9v-mfxr-j63j — urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API
- PYSEC-2026-142 — urllib3 is an HTTP client library for Python. From 2.6.0 to before 2.7.0, urllib3 could decompress the whole response instead of the requested portion (1) durin
European references
- ENISA EUVD · EUVD-2026-30047
- GCVE · GCVE-0-2026-44432
CERT-FR advisories
- CERTFR-2026-AVI-1385 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1378 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1206 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-1032 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0834 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0698 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:python:urllib3:*:*:*:*:*:*:*:*≥ 2.6.0 < 2.7.0
Affected products
| Product | Versions |
|---|---|
| urllib3 · urllib3 | affected >= 2.6.0, < 2.7.0 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |