How severe is GHSA-3x9g-8vmp-wqvf?

GHSA-3x9g-8vmp-wqvf has a CVSS score of 7.7/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-3x9g-8vmp-wqvf?

GHSA-3x9g-8vmp-wqvf affects the following packages: tornado (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-3x9g-8vmp-wqvf?

Update tornado to 6.5.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3x9g-8vmp-wqvf is resolved across your whole dependency graph.

How do I detect GHSA-3x9g-8vmp-wqvf in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tornado. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-3x9g-8vmp-wqvf if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against GHSA-3x9g-8vmp-wqvf?

O3 pinpoints whether GHSA-3x9g-8vmp-wqvf is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-3x9g-8vmp-wqvf actively exploited in the wild?

No public exploit code has been indexed for GHSA-3x9g-8vmp-wqvf yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-3x9g-8vmp-wqvf?

GHSA-3x9g-8vmp-wqvf has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 39th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-3x9g-8vmp-wqvf?

GHSA-3x9g-8vmp-wqvf is classified as Information Exposure (CWE-200). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-3x9g-8vmp-wqvf published, and has it been updated?

GHSA-3x9g-8vmp-wqvf was published on June 15, 2026 and was last updated on July 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

GHSA-3x9g-8vmp-wqvf

HIGH

Tornado: Authorization header forwarded across cross-origin redirects in SimpleAsyncHTTPClient

Also known asCVE-2026-49853PYSEC-2026-3387

Published

Jun 15, 2026

Updated

Jul 13, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk39th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐍tornado

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

When SimpleAsyncHTTPClient follows a 3xx redirect, it shallow-copies the original HTTPRequest, rewrites the URL, decrements max_redirects, and removes only the Host header. It does not clear Authorization, auth_username, auth_password, or auth_mode when the redirect target changes origin.

As a result, credentials intended for one origin can be forwarded to a different origin when follow_redirects=True, which is the default.

Beginning in Tornado 6.5.6, SimpleAsyncHTTPClient matches the default behavior of libcurl (and therefore CurlAsyncHTTPClient): When a redirect changes the scheme, host, or port of the url, the Authorization and Cookie headers will be removed when following the redirect.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`tornado`	all versions	6.5.6

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tornado. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update tornado to 6.5.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3x9g-8vmp-wqvf is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-3x9g-8vmp-wqvf is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-3x9g-8vmp-wqvf. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary When SimpleAsyncHTTPClient follows a 3xx redirect, it shallow-copies the original HTTPRequest, rewrites the URL, decrements max_redirects, and removes only the Host header. It does not clear Authorization, auth_username, auth_password, or auth_mode when the redirect target changes origin. As a result, credentials intended for one origin can be forwarded to a different origin when follow_redirects=True, which is the default. Beginning in Tornado 6.5.6, `SimpleAsyncHTTPClient` matches the default behavior of `libcurl` (and therefore `CurlAsyncHTTPClient`): When a redirect changes t

O3 Security · Impact-Aware SCA

Is GHSA-3x9g-8vmp-wqvf in your dependencies?

O3 detects GHSA-3x9g-8vmp-wqvf across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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