# CVE-2026-97687: urllib3: HTTPS proxy TLS configuration may be ignored or overridden > Attackers can intercept HTTPS proxy traffic by exploiting TLS configuration flaws in urllib3, allowing observation or modification of forwarded data. - **Severity:** High 7.6 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/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:** A user has to click or open something - **Fix available:** Yes - **Published:** 29 Sep 2026 - **Updated:** 30 Sep 2026 - **Also known as:** AZL-105651, AZL-105663, AZL-105678, AZL-105693, AZL-105909, BELL-CVE-2026-97687, CLEANSTART-2026-CZ57815, CLEANSTART-2026-DV56251, CLEANSTART-2026-DW54013, CLEANSTART-2026-GI85240, CLEANSTART-2026-IP34517, CLEANSTART-2026-TV45483, CLEANSTART-2026-YG47878, DEBIAN-CVE-2026-97687, ECHO-514d-4d4f-41d3, GHSA-8988-9cw3-xx77, MINI-22x9-835f-jw3x, MINI-272g-p234-h55r, MINI-35r6-hw7g-qvx4, MINI-3mvf-xhcf-f6gh, MINI-455p-6m6j-g954, MINI-4cm2-rf78-qpgv, MINI-69p4-hj9p-wv2q, MINI-6gg9-j92p-6v6m, MINI-7558-mhc5-qr5f, MINI-7jph-v749-v8f7, MINI-86jc-gfx8-ggw6, MINI-87hv-2c6x-r34m, MINI-cfcg-r2j4-5px9, MINI-fjqr-wfgx-9q8f, MINI-g38w-q5x9-pxqv, MINI-gg6j-8642-24q5, MINI-hx8g-6358-4qmr, MINI-hxhx-g3h5-55r8, MINI-j8m9-cv9v-c6wg, MINI-p475-jqh5-378g, MINI-p75w-8xwh-7f66, MINI-p965-prpv-pfr6, MINI-q249-3h2h-jqh9, MINI-qg33-fhxh-cw2m, MINI-qwjc-r95r-jgwr, MINI-qwq7-rqrx-6xx5, MINI-v875-5hrf-r39x, MINI-vvj7-r8gr-4fmf, MINI-vw2w-x9q4-8w82, MINI-wv9w-jhh3-pj4q, MINI-x2vf-6jx7-6hvj, MINI-x4f5-mwq3-5g37, MINI-x76q-jv9w-x9f5, MINI-xc98-v334-c3xq, OESA-2026-4624, OESA-2026-4626, OESA-2026-4627, PYSEC-2026-4175, ROOT-APP-PYPI-CVE-2026-97687, UBUNTU-CVE-2026-97687 ## What is CVE-2026-97687? CVE-2026-97687 is a high-severity vulnerability in urllib3, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official description urllib3 is an HTTP client library for Python. From 1.26.0 until 2.8.0, the proxy_ssl_context, proxy_assert_hostname, proxy_assert_fingerprint, ssl_context, cert_reqs, verify_mode, use_forwarding_for_https=True, and CERT_NONE configuration paths fail to remain separated because target-server TLS settings are incorrectly applied to the HTTPS proxy connection. The trigger is that an application uses an HTTPS proxy and configures target-server TLS settings that must remain separate from the proxy TLS handshake, including HTTPS forwarding with target-specific identity or credentials. Applying cert_reqs=CERT_NONE can overwrite proxy_ssl_context.verify_mode in place, and the mutation persists so later connections reusing the same context may connect to the HTTPS proxy without certificate verification. The attack mechanism is that an attacker intercepts and impersonates the HTTPS proxy after the effective proxy policy accepts the attacker's certificate. The impact is that the attacker can observe or modify forwarded traffic or receive a target TLS client certificate, while CONNECT tunneling still preserves the separate end-to-end target TLS connection. This issue is fixed in version 2.8.0. Weakness: CWE-440 (Expected Behavior Violation), CWE-295 (Improper Certificate Validation) ## Which versions are affected by CVE-2026-97687? 3 open source packages ship an affected version, including urllib3. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `urllib3` | PyPI | From 1.26.0 | 2.8.0 | | `urllib3` | PyPI | From 1.26.0 | 2.8.0 | | `urllib3` | PyPI | From 1.26.0 | 2.8.0 | Products: Python Urllib3. ## How do I fix CVE-2026-97687? Upgrade urllib3 to 2.8.0 or later. ## Is CVE-2026-97687 being exploited? There is no known exploitation of CVE-2026-97687 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-2026-97687 and fix it if it is affected. What it is: CVE-2026-97687 is a high-severity vulnerability in urllib3, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2026-97687 in the wild and no public exploit code. Affected packages and fixed versions: - urllib3 (PyPI): affected from 1.26.0; fixed in 2.8.0 - urllib3 (PyPI): affected from 1.26.0; fixed in 2.8.0 - urllib3 (PyPI): affected from 1.26.0; fixed in 2.8.0 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-2026-97687/ (Markdown: https://insights.sbomify.com/CVE-2026-97687/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97687 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97687 - OSV: https://osv.dev/vulnerability/CVE-2026-97687 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-97687/ Summaries are generated and may contain mistakes; the official description above is the record.