Security readout for executives and security teams
Plain-English summary
Bosch B426-family communication modules have a web configuration session weakness. An attacker with some access could hijack an admin's active web configuration session while the user is logged in, potentially affecting confidentiality, integrity, and availability of the device configuration.
Executive priority
Treat this as a high-priority operational technology and security-device management issue. Prioritize exposed or remotely administered devices first, because successful session hijacking could allow unauthorized configuration changes on security infrastructure.
Technical view
CVE-2021-23845 is an authentication bypass/session hijacking issue in Bosch B426, B426-CN/B429-CN, and B426-M firmware. The CVSS 3.1 score is 8.0, with network attack vector, low complexity, low privileges, required user interaction, and high impact to confidentiality, integrity, and availability.
Likely exposure
Exposure is most relevant where affected Bosch modules expose their configuration web page to reachable networks and administrators log in through that interface. The public source bundle does not specify exact vulnerable version ranges beyond stating fixes start with version 3.08.
Exploitation context
The source bundle does not report known active exploitation, and CISA KEV status is false. The scenario requires a logged-in configuration web user, so realistic risk depends on management-interface exposure, user activity, and attacker network reach.
Researcher notes
Affected version detail is incomplete in the provided sources. The strongest technical signals are CVSS 8.0, CWE-284, network reachability, low complexity, and session hijacking during an authenticated user's web configuration session. Avoid assuming exploit availability or broader Bosch product impact without vendor evidence.
Mitigation direction
- Upgrade affected firmware to version 3.08 or later where applicable.
- Review Bosch PSIRT guidance for model-specific remediation details.
- Restrict access to configuration web pages to trusted management networks.
- Avoid exposing the configuration interface directly to the internet.
- Review administrator access practices for affected devices.
Validation and detection
- Inventory Bosch B426-family modules and record exact firmware versions.
- Confirm whether any device runs firmware earlier than version 3.08.
- Check whether configuration web pages are reachable from untrusted networks.
- Review access logs for unusual configuration sessions, if available.
- Validate remediation against Bosch PSIRT documentation.
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-284: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2021-23845 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
- 8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
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.
CVSS vector scores
1 official scoreWe 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:L/UI:R/S:U/C:H/I:H/A:H2.15.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://psirt.bosch.com/security-advisories/bosch-sa-196933-bt.htmlCVE reference · x_refsource_CONFIRM
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.
Improper Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.