Hirschmann HiOS HiSecOS Authentication Bypass via HTTP Management
Hirschmann HiOS and HiSecOS products RSP, RSPE, RSPS, RSPL, MSP, EES, EESX, GRS, OS, RED, EAGLE contain an authentication bypass vulnerability in the HTTP(S) management module that allows unauthenticated remote attackers to gain administrative access by crafting specially formed HTTP requests. Attackers can exploit improper authentication handling to obtain the authentication status and privileges of a previously authenticated user without providing valid credentials.
- Published
- Apr 3, 2026
- Updated
- Jul 21, 2026
- EPSS
- 0.5% · 41th percentile
- CWE
- CWE-287
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Report tools
Action score
37
Monitor
Low priority for now.
- CVSS
- 37 / 40 · 9.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · VulnCheck
- 9.8
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
—
Versions reported by the vendor
Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.
Belden Hirschmann HiOS
- 06.1.05, 07.0.00, 03.1.00not affected
- up to and including 05.07affected
- up to and including 06.1.04affected
- up to and including 06.2.00affected
Belden Hirschmann HiSecOS EAGLE
- 03.0.03not affected
- up to and including 03.00.02affected
Same product
belden: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-27734Hirschmann HiOS 07.1.01, 07.1.02, and 08.1.00 through 08.5.xx and HiSecOS 03.3.00 through 03.5.01 allow remote attackers to change the crede39Monitor
- CVE-2020-6994A buffer overflow vulnerability was found in some devices of Hirschmann Automation and Control HiOS and HiSecOS.39Monitor
- CVE-2020-37216Hirschmann HiOS EtherNet/IP Stack Denial of Service34Monitor
- CVE-2020-9307Hirschmann OS2, RSP, and RSPE devices before HiOS 08.3.00 allow a denial of service.26Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- Integrity
- Availability
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- X
Weakness class (CWE)
CWE-287 · Improper AuthenticationCVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
nvd-secondary
Root cause
Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.
The bug in code
The whole CWE-287 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);Fixed
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Authentication AbuseCAPEC-114Medium
- Authentication BypassCAPEC-115Medium
- Identity SpoofingCAPEC-151likelihood: Medium · Medium
- Fake the Source of DataCAPEC-194Medium
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- Utilizing REST's Trust in the System Resource to Obtain Sensitive DataCAPEC-57likelihood: Medium · Very High
- Session HijackingCAPEC-593likelihood: High · Very High
- Token ImpersonationCAPEC-633Medium
ATT&CK techniques
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- assets.belden.com/m/52ecadbb5f1b0e04/original/Security-Bulletin-Web-Server-Authentication-Bypass-HiOS-HiSecOS-Hirschmann-BSECV-2018-05.pdf
- www.vulncheck.com/advisories/hirschmann-hios-hisecos-authentication-bypass-via-http-management
Vendor advisories and official records. Exploit/PoC links are deliberately left out.