GHSA-w248-ffj2-4v5q is a high-severity (CVSS 7.5) vulnerability in guzzlehttp/guzzle. A fix is available for guzzlehttp/guzzle — see the affected versions and patch details below.
Fix failure to strip Authorization header on HTTP downgrade
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-w248-ffj2-4v5q.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-w248-ffj2-4v5q by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
guzzlehttp/guzzle🐘guzzlehttp/guzzleReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Authorization headers on requests are sensitive information. On making a request using the https scheme to a server which responds with a redirect to a URI with the http scheme, we should not forward the Authorization header on. This is much the same as to how we don't forward on the header if the host changes. Prior to this fix, https to http downgrades did not result in the Authorization header being removed, only changes to the host.
Patches
Affected Guzzle 7 users should upgrade to Guzzle 7.4.4 as soon as possible. Affected users using any earlier series of Guzzle should upgrade to Guzzle 6.5.7 or 7.4.4.
Workarounds
An alternative approach would be to use your own redirect middleware, rather than ours, if you are unable to upgrade. If you do not require or expect redirects to be followed, one should simply disable redirects all together.
References
For more information
If you have any questions or comments about this advisory, please get in touch with us in #guzzle on the PHP HTTP Slack. Do not report additional security advisories in that public channel, however - please follow our vulnerability reporting process.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | guzzlehttp/guzzle | ≥ 4.0.0&&< 6.5.7 | 6.5.7composer require guzzlehttp/guzzle:^6.5.7 |
| 🐘Packagist | guzzlehttp/guzzle | ≥ 7.0.0&&< 7.4.4 | 7.4.4composer require guzzlehttp/guzzle:^7.4.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for guzzlehttp/guzzle, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update guzzlehttp/guzzle to 6.5.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w248-ffj2-4v5q 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.
Frequently Asked Questions
Is GHSA-w248-ffj2-4v5q in your dependencies?
Find it across Packagist, including transitive dependencies.