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Medium severity · published Sep 1, 2026
CVE-2026-78605
Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') in Elasticsearch Leading to Information Disclosure
5.9
CVSS
0.3%
EPSS
No
On KEV
Description
Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling') (CWE-444) in Elasticsearch can lead to information disclosure via HTTP Request Smuggling (CAPEC-33). Under specific proxy deployment configurations, a network attacker could obtain confidential responses intended for other authenticated users.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 27% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
EL
Elasticsearch · Elastic
8.18.0 through 8.19.19; 9.0.0 through 9.4.4; 9.5.0 · source: vendor, NVD
Affected product
EL
Elasticsearch
Elastic
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-78605
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-78605
Vendor Advisory
https://discuss.elastic.co/t/elasticsearch-8-19-20-9-4-5-9-5-1-security-update-esa-2026-141/390092
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