# CVE-2021-27633: Memory corruption in SAP NetWeaver AS for ABAP (RFC Gateway)

> An unauthenticated attacker can crash the SAP NetWeaver RFC Gateway by sending a specially crafted packet, causing a denial of service.

- **Severity:** High 7.5 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jun 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-pqvr-m7xp-v679

## What is CVE-2021-27633?

CVE-2021-27633 is a high-severity memory corruption vulnerability in SAP NetWeaver AS for ABAP (RFC Gateway), published on 9 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-27633?

It affects 1 product.


Products: Sap Netweaver Abap.

## How do I fix CVE-2021-27633?

No fix has been published for CVE-2021-27633 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-27633 being exploited?

There is no known exploitation of CVE-2021-27633 in the wild and no public exploit code.

## Other vulnerabilities in SAP NetWeaver AS for ABAP (RFC Gateway)

- [CVE-2012-4341](https://insights.sbomify.com/CVE-2012-4341/): Memory corruption in n/a (critical 10.0)
- [CVE-2021-27610](https://insights.sbomify.com/CVE-2021-27610/): Auth bypass in SAP NetWeaver AS ABAP and ABAP Platform (critical 9.0)
- [CVE-2021-38178](https://insights.sbomify.com/CVE-2021-38178/): Business logic in SAP NetWeaver AS ABAP and ABAP Platform (high 8.8)
- [CVE-2022-22543](https://insights.sbomify.com/CVE-2022-22543/): Denial of service in SAP NetWeaver Application Server for ABAP (Kernel) and ABAP Platform (Kernel) (high 7.5)
- [CVE-2021-38181](https://insights.sbomify.com/CVE-2021-38181/): Denial of service in SAP NetWeaver AS ABAP and ABAP Platform (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27633 and fix it if it is affected.

What it is: CVE-2021-27633 is a high-severity memory corruption vulnerability in SAP NetWeaver AS for ABAP (RFC Gateway), published on 9 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-27633 in the wild and no public exploit code.

Affected product: SAP NetWeaver AS for ABAP (RFC Gateway). No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-27633/ (Markdown: https://insights.sbomify.com/CVE-2021-27633/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27633
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27633
- OSV: https://osv.dev/vulnerability/CVE-2021-27633

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-27633/
Summaries are generated and may contain mistakes; the official description above is the record.