Answer in brief
CVE-2026-40542 records a High severity (CVSS 7.3) vulnerability in Apache HttpClient: SCRAM-SHA-256 mutual authentication bypass may cause the client to accept authentication without proper mutual authentication verification. The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/Apache HttpClient (generic), org.apache.httpcomponents.client5:httpclient5 (maven). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Apache Software Foundation/Apache HttpClient (generic), org.apache.httpcomponents.client5:httpclient5 (maven). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:apache:httpclient:5.6:-:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Apache Software Foundation/Apache HttpClientgeneric | >=5.6 <5.6.1 | 5.6.1 |
| org.apache.httpcomponents.client5:httpclient5maven | >=5.6-alpha1 <5.6.1 | 5.6.1 |
Published upstream
Apr 22, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 26, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 15, 2026
Missing critical step in authentication in Apache HttpClient 5.6 allows an attacker to cause the client to accept SCRAM-SHA-256 authentication without proper mutual authentication verification. Users are recommended to upgrade to version 5.6.1, which fixes this issue.
Quoted source text, attributed separately from HOL analysis.