5.9

CVE-2026-78605: elastic elasticsearch HTTP Request/Response Smuggling

CVSS: 5.9v3.1MediumAnalyzed
Published 01-09-2026Last modified 01-09-2026
Open JSON

Vulnerability summary

CVE-2026-78605 is a medium (CVSS 5.9) HTTP Request/Response Smuggling vulnerability in elastic elasticsearch. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.4% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.38%
0%100%
Low · +0.17 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 01-09-2026
    PublishedVulnerability first disclosed.
  2. 01-09-2026
    Last modifiedVulnerability information updated.

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 metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.38%

Chance of exploitation in the next 30 days

Percentile

30%

Versus all other CVEs

30-day change

+0.17 pp

From 0.21% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.38%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Elastic1 product
  • elasticsearch≥ 8.18.0, ≤ 8.19.19 | ≥ 9.0.0, ≤ 9.4.4 | ≥ 8.18.0, < 8.19.20 | ≥ 9.0.0, < 9.4.5 | 9.5.0

1 vendor · 1 product

References

1 links