Security readout for executives and security teams
Plain-English summary
Apache HttpClient 5.6 has an authentication flaw that may let a client accept SCRAM-SHA-256 authentication without properly verifying mutual authentication. This can weaken trust in authenticated connections. The named fix is upgrading to Apache HttpClient 5.6.1.
Executive priority
Treat as high priority for applications relying on Apache HttpClient 5.6 in authentication-sensitive paths. Upgrade planning should be prompt, but the source bundle does not support emergency exploitation claims.
Technical view
The issue is a missing critical authentication step in Apache HttpClient 5.6 affecting SCRAM-SHA-256 mutual authentication verification. It is tracked as CWE-304 and CWE-325 with CVSS 3.1 score 7.3, network exploitable, low complexity, no privileges, and no user interaction.
Likely exposure
Exposure appears limited to applications using Apache HttpClient 5.6, including package org.apache.httpcomponents.client5:httpclient5, particularly where SCRAM-SHA-256 authentication is used. The bundle does not identify other affected versions or downstream products.
Exploitation context
The bundle does not report active exploitation, and KEV is false. CVSS indicates remote reachability and low attack complexity, but the provided sources do not include exploit availability or observed attacks.
Researcher notes
Focus validation on dependency resolution and SCRAM-SHA-256 mutual authentication paths. The available evidence names the vulnerable version and fixed version, but does not provide deeper protocol traces, exploit status, or downstream product mapping.
Mitigation direction
- Upgrade Apache HttpClient to version 5.6.1.
- Inventory uses of org.apache.httpcomponents.client5:httpclient5 version 5.6.
- Prioritize systems using SCRAM-SHA-256 authentication flows.
- Check Apache and distribution advisories for downstream package guidance.
- Monitor Red Hat and vendor tracking for product-specific status.
Validation and detection
- Search dependency manifests and lockfiles for httpclient5 version 5.6.
- Confirm runtime artifacts do not bundle Apache HttpClient 5.6.
- Review authentication configuration for SCRAM-SHA-256 usage.
- Verify upgraded builds resolve to Apache HttpClient 5.6.1 or later.
- Document any vendor-packaged instances pending advisory confirmation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-304: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-325: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-40542 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L3.93.4redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-04-22T08:00:57.407Z: Reported to Red Hat.
- 2026-04-22T07:07:21.344Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://lists.apache.org/thread/tfmgv86xr0z1y096vs3z0y315t1v3o97CVE reference, apache · vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-40542CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2460518CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40542.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Critical Step in Authentication
Missing Critical Step in Authentication represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Missing Cryptographic Step
Missing Cryptographic Step represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.