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High, CVSS 7.6amended

urllib3: HTTPS proxy TLS configuration may be ignored or overridden

CVE-2026-97687GHSA-8988-9cw3-xx77

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (urllib3 2.8.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • PyPI urllib3

    Affected
    >= 1.26.0, < 2.8.0
    Fixed in
    2.8.0

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
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 · score source
EPSS
  • CVE-2026-97687: 0.21% estimated exploitation activity in the next 30 days; percentile 10.69 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Impact urllib3 supports configuring TLS independently for an HTTPS proxy and the target server. proxysslcontext, proxyasserthostname, and proxyassertfingerprint configure the TLS connection to the proxy. sslcontext and the other target-specific TLS parameters configure the connection to the target server. In urllib3 versions 1.26.0 through 2.7.0, these configurations were not consistently separated. Depending on the proxy mode, urllib3 could: 1. Ignore proxysslcontext and use the target server's SSL context for the TLS connection to an HTTPS forwarding proxy. 2. Override the HTTPS proxy's certificate-verification policy with the target server's certificate-verification policy. 3. Apply target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials to the TLS connection to an HTTPS forwarding proxy. In particular, configuring certreqs="CERTNONE" for a target server could overwrite the verifymode of the SSL context configured for the HTTPS…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 4 · amended ·

    Amended from ghsa record GHSA-8988-9cw3-xx77

  2. Revision 3 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 2 · amended ·

    Amended from osv record GHSA-8988-9cw3-xx77

  4. Revision 1 · created ·

    Published from ghsa record GHSA-8988-9cw3-xx77

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-97687

Advisory: urllib3: HTTPS proxy TLS configuration may be ignored or overridden
IDs: CVE-2026-97687, GHSA-8988-9cw3-xx77
Record: https://patchnext.com/advisories/cve-2026-97687 (revision 4, source checked 26 Oct 2026, 13:54 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: urllib3 2.8.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI urllib3: affected >= 1.26.0, < 2.8.0; fixed in 2.8.0

## Suggested inspection (read-only)
- `python -m pip show urllib3`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on urllib3.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-8988-9cw3-xx77 (GitHub-reviewed advisory GHSA-8988-9cw3-xx77 lists affected ranges: PyPI urllib3 >=1.26.0 <2.8.0)
- Verified: https://osv.dev/vulnerability/GHSA-8988-9cw3-xx77 (OSV record GHSA-8988-9cw3-xx77 lists affected ranges: PyPI urllib3 >=1.26.0 <2.8.0 (fixed))

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