CVE-2026-67355

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreHIGH confidence

Score 5.9 from GitHub Security Advisory (severity: HIGH) published 2026-08-01. a secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 0

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

guzzlehttp/guzzle versions before 7.15.1 fail to preserve host-only cookie scope, storing the request host in the Domain field instead of marking cookies as host-only. Attackers controlling child hosts can receive host-only cookies intended only for parent hosts, potentially disclosing session identifiers and authorization tokens when the same cookie jar is reused across trust boundaries.

CVSS v3
5.9
EG Score
5.9(high)
EG Risk
27(Track)
EG Risk 27/100SSVC: Track

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%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
13%
KEV
Not listed

Published

August 1, 2026

Last Modified

August 3, 2026

Advisory Details (2)

Auto-updated Aug 1, 2026
Patch available. Sources: github.
generic

guzzlehttp/guzzle before 7.15.1 Host-only Cookie Scope | Advisories | VulnCheck

https://www.vulncheck.com/advisories/guzzlehttp-guzzle-before-host-only-cookie-scope
github Patch Available

Host-only cookie scope is not preserved in guzzlehttp/guzzle · Advisory · guzzle/guzzle · GitHub

https://github.com/guzzle/guzzle/security/advisories/GHSA-wm3w-8rrp-j577

Vendor Advisories for CVE-2026-67355(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 rangeFixed inDependents
guzzle7.11.0-1 ... 8.0.1-1 (13 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
guzzle7.11.0-1 ... 8.0.1-1 (12 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
guzzle7.11.0-1 ... 7.9.2-0.1 (10 versions)7.15.1-1—
Packagist(1)
PackageVulnerable rangeFixed inDependents
guzzlehttp/guzzle4.0.0 ... v3.8.1 (174 versions)7.15.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 50× 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. 2026-08-25 23:22 UTCEG score recompute
  2. 2026-08-25 13:49 UTCEPSS rescore
  3. 2026-08-25 00:11 UTCEG score recompute
  4. 2026-08-23 02:01 UTCEG score recompute
  5. 2026-08-23 00:19 UTCEPSS rescore
  6. 2026-08-22 02:56 UTCEG score recompute
  7. 2026-08-21 23:49 UTCEPSS rescore
  8. 2026-08-21 03:50 UTCEG score recompute
  9. 2026-08-20 22:56 UTCEPSS rescore
  10. 2026-08-20 04:46 UTCEG score recompute
  11. 2026-08-19 17:04 UTCEPSS rescore
  12. 2026-08-19 05:40 UTCEG score recompute
  13. 2026-08-18 13:48 UTCEPSS rescore
  14. 2026-08-18 06:35 UTCEG score recompute
  15. 2026-08-17 13:47 UTCEPSS rescore
  16. 2026-08-17 07:30 UTCEG score recompute
  17. 2026-08-16 14:56 UTCEPSS rescore
  18. 2026-08-16 08:26 UTCEG score recompute
  19. 2026-08-15 09:21 UTCEG score recompute
  20. 2026-08-15 01:30 UTCEPSS rescore
  21. 2026-08-14 10:16 UTCEG score recompute
  22. 2026-08-13 22:00 UTCEPSS rescore
  23. 2026-08-13 11:11 UTCEG score recompute
  24. 2026-08-12 13:51 UTCEPSS rescore
  25. 2026-08-12 12:06 UTCEG score recompute
Show 25 more
  1. 2026-08-11 13:01 UTCEG score recompute
  2. 2026-08-11 00:00 UTCEPSS rescore
  3. 2026-08-09 14:51 UTCEG score recompute
  4. 2026-08-09 13:47 UTCEPSS rescore
  5. 2026-08-08 16:37 UTCEPSS rescore
  6. 2026-08-07 16:42 UTCEG score recompute
  7. 2026-08-06 17:37 UTCEG score recompute
  8. 2026-08-06 13:47 UTCEPSS rescore
  9. 2026-08-05 19:17 UTCEPSS rescore
  10. 2026-08-05 19:17 UTCEPSS rescore
  11. 2026-08-04 19:26 UTCEG score recompute
  12. 2026-08-04 15:10 UTCEPSS rescore
  13. 2026-08-04 10:39 UTCEPSS rescore
  14. 2026-08-03 20:20 UTCEG score recompute
  15. 2026-08-03 20:20 UTCGHSA enrichment
  16. 2026-08-03 20:14 UTCEG score recompute
  17. 2026-08-03 20:14 UTCGHSA enrichment
  18. 2026-08-03 11:32 UTCEG score recompute
  19. 2026-08-03 11:31 UTCGHSA enrichment
  20. 2026-08-03 10:36 UTCEPSS rescore
  21. 2026-08-02 12:24 UTCEG score recompute
  22. 2026-08-02 12:24 UTCGHSA enrichment
  23. 2026-08-01 13:19 UTCEG score recompute
  24. 2026-08-01 12:44 UTCEG score recompute
  25. 2026-08-01 12:42 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-67355?
CVE-2026-67355 is a medium vulnerability published on August 1, 2026. guzzlehttp/guzzle versions before 7.15.1 fail to preserve host-only cookie scope, storing the request host in the Domain field instead of marking cookies as host-only. Attackers controlling child hosts can receive host-only cookies intended only for parent hosts, potentially disclosing session…
When was CVE-2026-67355 disclosed?
CVE-2026-67355 was first published in the National Vulnerability Database on August 1, 2026, with the most recent update on August 3, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-67355 actively exploited?
CVE-2026-67355 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 86.5% of all scored CVEs.
What is the CVSS score of CVE-2026-67355?
CVE-2026-67355 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-67355?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-67355, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-67355

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