# CVE-2026-44431: urllib3: Sensitive headers forwarded across origins in proxied low-level redirects > Attackers can steal sensitive headers during cross-origin redirects in urllib3's low-level API when using ProxyManager with assert_same_host disabled. - **Severity:** High 8.2 (`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`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 13 May 2026 - **Updated:** 26 Jun 2026 - **Also known as:** ALSA-2026:36732, ALSA-2026:47126, ALSA-2026:49927, AZL-86862, BELL-CVE-2026-44431, CLEANSTART-2026-KM03146, CLEANSTART-2026-RV30467, CLSA-2026-1782176234, CLSA-2026-1782954023, CLSA-2026-1789549824, CLSA-2026-1791187923, DEBIAN-CVE-2026-44431, ECHO-4544-3b20-7e41, GHSA-qccp-gfcp-xxvc, MINI-35pg-r928-4499, MINI-3xgc-53cx-ff5f, MINI-43r4-8hqh-5h4m, MINI-76w6-v44w-v7h2, MINI-84hp-38gr-rfh3, MINI-8q84-p6cw-jf4m, MINI-8qx6-49gc-px7w, MINI-9239-94jq-89wm, MINI-92cw-2ghh-pmc6, MINI-94wh-7573-89j9, MINI-cpjh-v7g2-m78j, MINI-cq9q-52qr-4gx6, MINI-f8xm-8p79-g739, MINI-gq25-6xcx-cgq4, MINI-jh59-7mfp-3w3r, MINI-jrcj-3f3v-jhhf, MINI-mmr8-mqh6-2gjw, MINI-p78w-wrc3-6px4, MINI-q3qg-9x57-28hh, MINI-qpwf-cf8r-jrff, MINI-rg8j-qh5v-g255, MINI-rm77-hpxh-jw9f, MINI-v36v-6m24-79r2, MINI-v6jm-jvrh-rqp4, MINI-wfxv-rvvg-7v37, MINI-x462-8h5j-whjm, MINI-xhwv-w54c-3gmc, MINI-xrx5-m4gh-h4vh, MINI-xv59-x34r-45gm, OESA-2026-2298, OESA-2026-2299, OESA-2026-2300, OESA-2026-2390, OESA-2026-2391, OESA-2026-2543, PYSEC-2026-141, RHSA-2026:30169, RHSA-2026:36732, RHSA-2026:47091, RHSA-2026:47092, RHSA-2026:47126, RHSA-2026:47129, RHSA-2026:49927, RHSA-2026:51045, RHSA-2026:51152, RHSA-2026:51157, RLSA-2026:36732, RLSA-2026:47126, RLSA-2026:49927, ROOT-APP-PYPI-CVE-2026-44431, SUSE-SU-2026:2065-1, SUSE-SU-2026:2067-1, SUSE-SU-2026:2119-1, SUSE-SU-2026:21728-1, SUSE-SU-2026:21741-1, SUSE-SU-2026:21955-1, SUSE-SU-2026:22003-1, SUSE-SU-2026:22011-1, SUSE-SU-2026:2486-1, UBUNTU-CVE-2026-44431, USN-8811-1, openSUSE-SU-2026:10838-1, openSUSE-SU-2026:20861-1, openSUSE-SU-2026:20871-1 ## What is CVE-2026-44431? CVE-2026-44431 is a high-severity vulnerability in urllib3, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0. Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) ## Which versions are affected by CVE-2026-44431? 3 open source packages ship an affected version, including urllib3. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `urllib3` | PyPI | From 1.23 | 2.7.0 | | `urllib3` | PyPI | From 1.23 | 2.7.0 | | `urllib3` | PyPI | From 1.23 | 2.7.0 | | `fence-agents-aliyun` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-all` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-amt-ws` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-apc` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-apc-snmp` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-aws` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-azure-arm` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-bladecenter` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-brocade` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-cisco-mds` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-cisco-ucs` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-common` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-compute` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-drac5` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-eaton-snmp` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-emerson` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-eps` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-gce` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-heuristics-ping` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-hpblade` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ibm-powervs` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ibm-vpc` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ibmblade` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ifmib` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ilo-moonshot` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ilo-mp` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ilo-ssh` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ilo2` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-intelmodular` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ipdu` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-ipmilan` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-kdump` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-kubevirt` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-lpar` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-mpath` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-nutanix-ahv` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | | `fence-agents-openstack` | AlmaLinux:8 | All versions | 4.2.1-129.el8_10.28 | Products: Python Urllib3. ## How do I fix CVE-2026-44431? Upgrade urllib3 to 2.7.0 or later. ## Is CVE-2026-44431 being exploited? There is no known exploitation of CVE-2026-44431 in the wild and no public exploit code. ## Other vulnerabilities in urllib3 - [CVE-2026-97689](https://insights.sbomify.com/CVE-2026-97689/): urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory (high 8.9) - [CVE-2026-44432](https://insights.sbomify.com/CVE-2026-44432/): urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API (high 8.9) - [CVE-2026-21441](https://insights.sbomify.com/CVE-2026-21441/): urllib3 vulnerable to decompression-bomb safeguard bypass when following HTTP redirects (streaming API) (high 8.9) - [CVE-2025-66418](https://insights.sbomify.com/CVE-2025-66418/): urllib3 allows an unbounded number of links in the decompression chain (high 8.9) - [CVE-2025-66471](https://insights.sbomify.com/CVE-2025-66471/): urllib3 Streaming API improperly handles highly compressed data (high 8.9) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-44431 and fix it if it is affected. What it is: CVE-2026-44431 is a high-severity vulnerability in urllib3, published on 13 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-44431 in the wild and no public exploit code. Affected packages and fixed versions: - urllib3 (PyPI): affected from 1.23; fixed in 2.7.0 - urllib3 (PyPI): affected from 1.23; fixed in 2.7.0 - urllib3 (PyPI): affected from 1.23; fixed in 2.7.0 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-44431/ (Markdown: https://insights.sbomify.com/CVE-2026-44431/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44431 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44431 - OSV: https://osv.dev/vulnerability/CVE-2026-44431 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-44431/ Summaries are generated and may contain mistakes; the official description above is the record.