# CVE-2021-27218: Integer overflow in n/a

> An integer overflow in GLib's g_byte_array_new_take() causes length truncation for buffers over 4GB, potentially leading to memory corruption or logic errors.

- **Severity:** High 7.5 (`CVSS:3.1/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:** Yes
- **Published:** 15 Feb 2021
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2021-27218, ALSA-2021:3058, AZL-6437, CLSA-2023-1696352100, DEBIAN-CVE-2021-27218, GHSA-vvj7-w55j-xgmw, JLSEC-2025-156, RHSA-2021:3058, RLSA-2021:3058, UBUNTU-CVE-2021-27218

## What is CVE-2021-27218?

CVE-2021-27218 is a high-severity vulnerability in Debian Debian Linux, published on 15 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in GNOME GLib before 2.66.7 and 2.67.x before 2.67.4. If g_byte_array_new_take() was called with a buffer of 4GB or more on a 64-bit platform, the length would be truncated modulo 2**32, causing unintended length truncation.

Weakness: CWE-681 (Incorrect Conversion between Numeric Types)

## Which versions are affected by CVE-2021-27218?

It affects 7 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `glib2-doc` | AlmaLinux:8 | All versions | 2.56.4-10.el8_4.1 |
| `glib2-static` | AlmaLinux:8 | All versions | 2.56.4-10.el8_4.1 |
| `glib2` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-devel` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-devel-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-fam` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-fam-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-tests` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-tests-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-debugsource` | Red Hat:enterprise_linux:8::crb | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-devel-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-doc` | Red Hat:enterprise_linux:8::crb | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-fam-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-static` | Red Hat:enterprise_linux:8::crb | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2-tests-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 0:2.56.4-10.el8_4.1 |
| `glib2` | Rocky Linux:8 | All versions | 0:2.56.4-10.el8_4.1 |

Products: Broadcom Brocade Fabric Operating System Firmware, Debian Debian Linux, Fedoraproject Fedora, Gnome Glib, Netapp Active Iq Unified Manager, Netapp Cloud Backup, Netapp E-Series Performance Analyzer.

## How do I fix CVE-2021-27218?

Upgrade to a fixed version.

## Is CVE-2021-27218 being exploited?

There is no known exploitation of CVE-2021-27218 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2023-27534](https://insights.sbomify.com/CVE-2023-27534/): Path traversal in https://github.com/curl/curl (high 8.8)
- [CVE-2021-4197](https://insights.sbomify.com/CVE-2021-4197/): Privilege escalation in kernel (high 7.8)
- [CVE-2023-27538](https://insights.sbomify.com/CVE-2023-27538/): Auth bypass in https://github.com/curl/curl (high 7.7)
- [CVE-2021-27219](https://insights.sbomify.com/CVE-2021-27219/): Integer overflow in n/a (high 7.5)
- [CVE-2019-19044](https://insights.sbomify.com/CVE-2019-19044/): Denial of service in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-27218 and fix it if it is affected.

What it is: CVE-2021-27218 is a high-severity vulnerability in Debian Debian Linux, published on 15 Feb 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-2021-27218 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2021-27218/ (Markdown: https://insights.sbomify.com/CVE-2021-27218/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-27218
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-27218
- OSV: https://osv.dev/vulnerability/CVE-2021-27218

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-27218/
Summaries are generated and may contain mistakes; the official description above is the record.