CVE-2026-55767

MEDIUMPre-NVD 5.85.8—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 98% 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
5.8
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.8Exploit: 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, CookieJar incorrectly accepts cookies with a dot-only Domain attribute and whitespace-padded variants. SetCookie::matchesDomain() removes leading dots from the cookie domain, normalizing dot-only values to the empty string; SetCookie::validate() only rejected a strictly empty domain, so these cookies could be stored and the empty normalized domain was treated as matching any request host. An attacker-controlled origin that an application requests with a shared cookie jar can therefore set a cookie that Guzzle later sends to unrelated hosts using the same jar. This may allow cookie injection or session fixation against downstream services, depending on how those services interpret the injected cookie. This vulnerability is fixed in 7.12.1.

CVSS v3
5.8
EG Score
5.8(medium)
EPSS
1.6%
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

Dot-Only Cookie Domains Match All Hosts in guzzlehttp/guzzle · Advisory · guzzle/guzzle · GitHub

https://github.com/guzzle/guzzle/security/advisories/GHSA-cwxw-98qj-8qjx

Vendor Advisories for CVE-2026-55767(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(2)

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

Data Freshness Timeline

(refreshed 17× in last 7d / 36× 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. 2026-07-07 04:21 UTCEG score recompute
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 04:56 UTCEG score recompute
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-06 02:23 UTCEPSS rescore
  7. 2026-07-05 05:34 UTCEG score recompute
  8. 2026-07-05 02:31 UTCEPSS rescore
  9. 2026-07-05 02:30 UTCEPSS rescore
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-04 06:31 UTCEPSS rescore
  12. 2026-07-04 06:03 UTCEG score recompute
  13. 2026-07-03 06:40 UTCEG score recompute
  14. 2026-07-02 07:19 UTCEG score recompute
  15. 2026-07-01 15:07 UTCEPSS rescore
  16. 2026-07-01 08:00 UTCEG score recompute
  17. 2026-06-30 23:22 UTCEPSS rescore
  18. 2026-06-30 08:40 UTCEG score recompute
  19. 2026-06-29 14:06 UTCEPSS rescore
  20. 2026-06-29 14:06 UTCEPSS rescore
  21. 2026-06-29 09:20 UTCEG score recompute
  22. 2026-06-28 14:07 UTCEPSS rescore
  23. 2026-06-28 10:00 UTCEG score recompute
  24. 2026-06-28 04:56 UTCEPSS rescore
  25. 2026-06-28 04:56 UTCEPSS rescore
Show 11 more
  1. 2026-06-27 10:40 UTCEG score recompute
  2. 2026-06-27 03:08 UTCEPSS rescore
  3. 2026-06-26 11:20 UTCEG score recompute
  4. 2026-06-25 11:12 UTCEG score recompute
  5. 2026-06-24 14:05 UTCEPSS rescore
  6. 2026-06-24 11:50 UTCEG score recompute
  7. 2026-06-23 12:31 UTCEG score recompute
  8. 2026-06-22 13:04 UTCEG score recompute
  9. 2026-06-21 13:44 UTCEG score recompute
  10. 2026-06-20 14:19 UTCEG score recompute
  11. 2026-06-19 14:56 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-55767?
CVE-2026-55767 is a medium vulnerability published on June 19, 2026. Guzzle is an extensible PHP HTTP client. Prior to 7.12.1, CookieJar incorrectly accepts cookies with a dot-only Domain attribute and whitespace-padded variants. SetCookie::matchesDomain() removes leading dots from the cookie domain, normalizing dot-only values to the empty string;…
When was CVE-2026-55767 disclosed?
CVE-2026-55767 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-2026-55767 actively exploited?
CVE-2026-55767 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-55767?
CVE-2026-55767 has a CVSS v3 base score of 5.8 (NVD).
How do I remediate CVE-2026-55767?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55767, 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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