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Netweaver AbapApplication · Sap

CVE-2021-27610

CRITICAL · 9.8 CVSS v3.1 Published 2021-06-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
SAP NetWeaver ABAP Server and ABAP Platform, versions - 700, 701, 702, 731, 740, 750, 751, 752, 753, 754, 755, 804, does not create information about internal and external RFC user in consistent and distinguished format, which could lead to improper authentication and may be exploited by malicious users to obtain illegitimate access to the system.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

SAP NetWeaver ABAP Server fails to maintain a consistent and distinguished format for internal versus external RFC (Remote Function Call) user authentication, creating an authentication bypass vector where malicious users can obtain illegitimate system access through improperly distinguished RFC user contexts.

MitigationApply SAP Security Notes addressing CVE-2021-27610 to implement proper RFC user differentiation in authentication mechanisms; verify RFC user configurations conform to SAP security guidelines.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Netweaver AbapApplication
Affected:= 700= 701= 702= 731= 740= 750= 751= 752= 753= 754= 755= 804
Netweaver Application Server AbapApplication
Affected:= 700= 701= 702= 731= 740= 750= 751= 752= 753= 754= 755= 804

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check ABAP server version
    Execute transaction SM51 or use transaction ST03 to view the SAP System Release and Kernel version. Alternatively, check the SAP System Overview in transaction SMICM.
    Affected if The installed version matches 700, 701, 702, 731, 740, 750, 751, 752, 753, 754, 755, or 804.
  2. Identify configured RFC users
    Use transaction SU01 to list users with RFC authorization profiles. Check table USR02 for users with RFC-relevant profiles. Review transaction SIDADM which is the default SAP System RFC user.
    Affected if Any RFC-enabled users exist in the system (particularly SIDADM or users with RFC authorizations).
  3. Review RFC user type classification
    Use transaction SU01 to inspect RFC users and verify whether they are properly classified as 'Internal RFC' or 'External RFC' users according to SAP security guidelines. Check the user type field in the user master record.
    Affected if RFC users lack proper internal/external distinction or have ambiguous user type settings.
  4. Verify RFC authorizations
    Use transaction SU03 or check user authorization profiles via transaction SU56 for RFC-related authorizations (such as S_RFC). Examine whether RFC users have overly broad function module access.
    Affected if RFC users have unrestricted or improperly scoped RFC authorizations that could enable authentication bypass.
  5. Audit recent RFC logon attempts
    Review transaction SM19 (Security Audit Log) or SM37 for RFC-based logon events. Check for anomalous RFC connections or unexpected source systems.
    Affected if Unusual RFC logon patterns or connections from unexpected sources are observed.

If the system runs an affected version (700-755 or 804) and uses RFC users with improperly distinguished internal/external authentication contexts, the environment is likely affected by this authentication bypass vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply SAP Security Notes addressing CVE-2021-27610 to implement proper RFC user differentiation in authentication mechanisms; verify RFC user configurations conform to SAP security guidelines.

Fix this in Netweaver Abap Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-27610 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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