CVE-2021-27631Network attack vector

Unauthenticated service crash via null pointer dereference

Published Jun 9, 2021 · Updated Aug 3, 2024

NULL pointer dereference in SAP NetWeaver AS ABAP's Enqueue Server allows remote attackers to crash the service with a crafted packet. EnqConvUniToSrvReq calculates part of a message's size from attacker-controlled packet content and dereferences a null pointer. No authentication or system knowledge is required; the result is an availability-only service interruption with no data read or modification.

CVSS severity7.5
High
EPSS probability1.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in SAP NetWeaver AS ABAP's Enqueue Server allows remote attackers to crash the service with a crafted packet. EnqConvUniToSrvReq calculates part of a message's size from attacker-controlled packet content and dereferences a null pointer. No authentication or system knowledge is required; the result is an availability-only service interruption with no data read or modification.

The record

CVE
CVE-2021-27631
Published
Jun 9, 2021
Updated
Aug 3, 2024
Vendor
SAP SE
Product
SAP NetWeaver AS ABAP
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 9, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 7.22
  2. Affected versionversion=< 7.22EXT
  3. Affected versionversion=< 7.49
  4. Affected versionversion=< 7.53
  5. Affected versionversion=< 7.73
  6. Affected versionversion=< 8.04
  7. Affected versionversion=< KERNEL - 7.22
  8. Affected versionversion=< KRNL32NUC - 7.22
  9. Affected versionversion=< KRNL64NUC - 7.22
  10. Affected versionversion=< KRNL64UC - 8.04

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SAP SE · SAP NetWeaver AS ABAPversion=< 7.22; version=< 7.22EXT; version=< 7.49; version=< 7.53; version=< 7.73; version=< 8.04; version=< KERNEL - 7.22; version=< KRNL32NUC - 7.22; version=< KRNL64NUC - 7.22; version=< KRNL64UC - 8.04

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5SAP SECVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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