How severe is CVE-2021-27633?

CVE-2021-27633 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-27633 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27633?

CVE-2021-27633 primarily affects Sap Netweaver Abap. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-27633?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-27633 published?

CVE-2021-27633 was published on 2021-06-09 and last updated on 2026-06-17.

CVE-2021-27633

CVE-2021-27633 is a high-severity vulnerability in Sap Netweaver Abap with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Sap Netweaver Abap
Published: 2021-06-09
Last modified: 2026-06-17

Description

SAP NetWeaver AS for ABAP (RFC Gateway), versions - KRNL32NUC - 7.22,7.22EXT, KRNL64NUC - 7.22,7.22EXT,7.49, KRNL64UC - 8.04,7.22,7.22EXT,7.49,7.53,7.73, KERNEL - 7.22,8.04,7.49,7.53,7.73,7.77,7.81,7.82,7.83, allows an unauthenticated attacker without specific knowledge of the system to send a specially crafted packet over a network which will trigger an internal error in the system due to improper input validation in method ThCPIC() causing the system to crash and rendering it unavailable. In this attack, no data in the system can be viewed or modified.

Frequently asked questions

What is CVE-2021-27633?: SAP NetWeaver AS for ABAP (RFC Gateway), versions - KRNL32NUC - 7.22,7.22EXT, KRNL64NUC - 7.22,7.22EXT,7.49, KRNL64UC - 8.04,7.22,7.22EXT,7.49,7.53,7.73, KERNEL - 7.22,8.04,7.49,7.53,7.73,7.77,7.81,7.82,7.83, allows an unauthenticated attacker without specific knowledge of the system to send a specially crafted packet over a network which will trigger an internal error in the system due to improper input validation in method ThCPIC() causing the system to crash and rendering it unavailable. In this attack, no data in the system can be viewed or modified.
How severe is CVE-2021-27633?: CVE-2021-27633 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-27633 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27633?: CVE-2021-27633 primarily affects Sap Netweaver Abap. In total, 16 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-27633?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27633 published?: CVE-2021-27633 was published on 2021-06-09 and last updated on 2026-06-17.

References

Affected products (16)

cpe:2.3:a:sap:netweaver_abap:kernel_7.22:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:kernel_7.49:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:kernel_7.53:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:kernel_7.73:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:kernel_8.04:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl32nuc_7.22:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl32nuc_7.22ext:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64nuc_7.22:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64nuc_7.22ext:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64nuc_7.49:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64uc_7.22:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64uc_7.22ext:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64uc_7.49:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64uc_7.53:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64uc_7.73:*:*:*:*:*:*:*
cpe:2.3:a:sap:netweaver_abap:krnl64uc_8.04:*:*:*:*:*:*:*

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