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 96% 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
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
5.9MEDIUMmedium confidence
EG Risk
27
EG Risk 27/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
EPSS PROB
0.1%
EPSS %ILE
3rd
KEV
Not listed

Published

June 19, 2026

Last Modified

June 26, 2026

Advisory Details (1)

Auto-updated Jun 23, 2026
Patch available. Sources: github.
githubMentions a patch (unverified)

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

(4 across 4 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
guzzle7.11.0-1 ... 8.2.0-1 (19 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
guzzle7.11.0-1 ... 8.2.0-1 (18 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
guzzle7.11.0-1, 7.12.0-1, 7.9.2-0.1
  • every version up to 7.12.1-1: fixed in 7.12.1-1
—
Packagist(1)
PackageVulnerable rangeFix by version rangeDependents
guzzlehttp/guzzle4.0.0 ... v3.8.1 (163 versions)
  • every version up to 7.12.1: fixed in 7.12.1
—

Weakness Classification(3)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 26× 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.

Showing the most recent 100 of 119 total refreshes for this CVE.

  1. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-08 17:12 UTCEPSS rescore
  3. 2026-10-07 23:48 UTCEPSS rescore
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  9. 2026-10-02 15:11 UTCOSV refresh
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  24. 2026-09-13 13:16 UTCEG score recompute
  25. 2026-09-11 14:53 UTCEPSS rescore
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  1. 2026-09-10 09:35 UTCEPSS rescore
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  9. 2026-08-30 20:52 UTCEG score recompute
  10. 2026-08-30 19:17 UTCEPSS rescore
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  19. 2026-08-22 23:56 UTCEG score recompute
  20. 2026-08-21 23:49 UTCEPSS rescore
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  22. 2026-08-20 22:55 UTCEPSS rescore
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  24. 2026-08-17 13:47 UTCEPSS rescore
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  26. 2026-08-16 14:56 UTCEPSS rescore
  27. 2026-08-16 10:36 UTCEG score recompute
  28. 2026-08-16 02:14 UTCEPSS rescore
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  31. 2026-08-14 06:47 UTCEG score recompute
  32. 2026-08-13 22:00 UTCEPSS rescore
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  34. 2026-08-12 13:51 UTCEPSS rescore
  35. 2026-08-12 03:34 UTCEG score recompute
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  37. 2026-08-09 13:46 UTCEPSS rescore
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  39. 2026-08-08 16:37 UTCEPSS rescore
  40. 2026-08-07 21:07 UTCEG score recompute
  41. 2026-08-06 19:30 UTCEG score recompute
  42. 2026-08-06 13:47 UTCEPSS rescore
  43. 2026-08-05 19:17 UTCEPSS rescore
  44. 2026-08-04 15:58 UTCEG score recompute
  45. 2026-08-04 15:10 UTCEPSS rescore
  46. 2026-08-04 10:39 UTCEPSS rescore
  47. 2026-08-03 14:21 UTCEG score recompute
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  49. 2026-08-02 09:28 UTCEG score recompute
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  52. 2026-08-01 04:16 UTCEPSS rescore
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  54. 2026-07-30 16:28 UTCEPSS rescore
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  59. 2026-07-27 18:37 UTCEG score recompute
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  61. 2026-07-26 14:54 UTCEPSS rescore
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  64. 2026-07-23 03:20 UTCEG score recompute
  65. 2026-07-22 14:08 UTCEPSS rescore
  66. 2026-07-21 15:25 UTCEPSS rescore
  67. 2026-07-19 14:31 UTCEPSS rescore
  68. 2026-07-19 14:31 UTCEPSS rescore
  69. 2026-07-16 17:03 UTCEPSS rescore
  70. 2026-07-15 16:57 UTCEPSS rescore
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  72. 2026-07-13 22:31 UTCEPSS rescore
  73. 2026-07-12 05:46 UTCEPSS rescore
  74. 2026-07-09 19:10 UTCEPSS rescore
  75. 2026-07-09 19:10 UTCEPSS rescore

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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 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 0.1% probability of exploitation in the next 30 days (3rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55568?
CVE-2026-55568 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55568?
A fix for CVE-2026-55568 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55568 are linked in the Vendor Advisories panel on this page.

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