CVE-2026-55568

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
5.9
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.9Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, in certain configurations, traffic expected to be protected by TLS on the hop to the proxy is transmitted in cleartext. Proxy authentication credentials (the Proxy-Authorization header, proxy userinfo in the proxy URL, or CURLOPT_PROXYUSERPWD) are sent without encryption, and the CONNECT target host and port for tunneled HTTPS requests are exposed. The built-in cURL handlers (GuzzleHttp\Handler\CurlHandler and GuzzleHttp\Handler\CurlMultiHandler, used by default whenever the PHP cURL extension is available) accept an https:// proxy. libcurl older than 7.50.2 silently treats an https:// proxy as a plaintext http:// proxy. The TLS connection to the proxy is never established, and the proxy leg is cleartext with no error or warning. An application is affected when it sends requests through one of the built-in cURL handlers, configures an https:// proxy expecting the proxy connection itself to be encrypted, and runs with libcurl older than 7.50.2. This vulnerability is fixed in 7.12.1.

CVSS v3
5.9
EG Score
5.9(medium)
EPSS
1.3%
KEV
Not listed

Published

June 19, 2026

Last Modified

June 26, 2026

Advisory Details (1)

Auto-updated Jun 23, 2026
Patch available. Sources: github.
github Patch Available

Silent HTTPS-Proxy Downgrade to Cleartext in guzzlehttp/guzzle · Advisory · guzzle/guzzle · GitHub

https://github.com/guzzle/guzzle/security/advisories/GHSA-wpwq-4j6v-78m3

Vendor Advisories for CVE-2026-55568(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
guzzlehttp/guzzle4.0.0 ... v3.8.1 (163 versions)7.12.1—

Weakness Classification(3)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 31× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-06 19:00 UTCEG score recompute
  2. 2026-07-05 16:23 UTCEG score recompute
  3. 2026-07-05 02:31 UTCEPSS rescore
  4. 2026-07-05 02:30 UTCEPSS rescore
  5. 2026-07-04 14:37 UTCEG score recompute
  6. 2026-07-04 06:31 UTCEPSS rescore
  7. 2026-07-04 06:31 UTCEPSS rescore
  8. 2026-07-03 13:00 UTCEG score recompute
  9. 2026-07-02 11:08 UTCEG score recompute
  10. 2026-07-01 15:07 UTCEPSS rescore
  11. 2026-07-01 09:07 UTCEG score recompute
  12. 2026-06-30 23:22 UTCEPSS rescore
  13. 2026-06-30 07:29 UTCEG score recompute
  14. 2026-06-29 14:06 UTCEPSS rescore
  15. 2026-06-29 14:06 UTCEPSS rescore
  16. 2026-06-29 05:50 UTCEG score recompute
  17. 2026-06-28 14:07 UTCEPSS rescore
  18. 2026-06-28 04:56 UTCEPSS rescore
  19. 2026-06-28 04:56 UTCEPSS rescore
  20. 2026-06-28 04:12 UTCEG score recompute
  21. 2026-06-27 03:08 UTCEPSS rescore
  22. 2026-06-27 02:33 UTCEG score recompute
  23. 2026-06-26 00:52 UTCEG score recompute
  24. 2026-06-25 13:49 UTCEPSS rescore
  25. 2026-06-24 23:15 UTCEG score recompute
Show 6 more
  1. 2026-06-24 14:05 UTCEPSS rescore
  2. 2026-06-23 21:39 UTCEG score recompute
  3. 2026-06-22 19:59 UTCEG score recompute
  4. 2026-06-21 18:20 UTCEG score recompute
  5. 2026-06-20 16:43 UTCEG score recompute
  6. 2026-06-19 14:57 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-55568?
CVE-2026-55568 is a medium vulnerability published on June 19, 2026. Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, in certain configurations, traffic expected to be protected by TLS on the hop to the proxy is transmitted in cleartext. Proxy authentication credentials (the Proxy-Authorization header, proxy userinfo in the proxy URL, or…
When was CVE-2026-55568 disclosed?
CVE-2026-55568 was first published in the National Vulnerability Database on June 19, 2026, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55568 actively exploited?
CVE-2026-55568 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55568?
CVE-2026-55568 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-55568?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55568, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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