CVE-2026-97687

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-24 21:43 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-09-29 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-10-13 20:27 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: 7.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-09-29 16:17 UTC

Last modified

2026-10-13 20:27 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-295 · Improper certificate validation

Record status

Analyzed

Affected

• Python urllib3 < 2.8.0

Attack profile CVSS 4.0 · 7.6

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

Passive

Confidentiality

High

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-97687.md and follow it. Check whether this project is affected by CVE-2026-97687. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

Copy as ticket · More options · Status badge