# CVE-2022-28733: Integer underflow in grub_net_recv_ip4_packets > A malicious IP packet causes an integer underflow in GRUB, potentially allowing buffer overflows and arbitrary code execution during boot. - **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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:** 20 Jul 2023 - **Updated:** 13 Feb 2025 - **Also known as:** AZL-27553, AZL-34788, DEBIAN-CVE-2022-28733, GHSA-2rxj-vwp2-v63v, RHSA-2022:8900, UBUNTU-CVE-2022-28733 ## What is CVE-2022-28733? CVE-2022-28733 is a high-severity vulnerability in GNU GRUB, published on 20 Jul 2023. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Integer underflow in grub_net_recv_ip4_packets; A malicious crafted IP packet can lead to an integer underflow in grub_net_recv_ip4_packets() function on rsm->total_len value. Under certain circumstances the total_len value may end up wrapping around to a small integer number which will be used in memory allocation. If the attack succeeds in such way, subsequent operations can write past the end of the buffer. Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound)) ## Which versions are affected by CVE-2022-28733? It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `grub2` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-common` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-debuginfo` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-aa64-modules` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-ia32` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-ia32-cdboot` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-ia32-modules` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-x64` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-x64-cdboot` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-x64-modules` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-pc` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-pc-modules` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc-modules` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc64-modules` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc64le-modules` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-tools` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-tools-extra` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-tools-minimal` | Red Hat:enterprise_linux:7::client | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-debuginfo` | Red Hat:enterprise_linux:7::computenode | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-aa64-modules` | Red Hat:enterprise_linux:7::computenode | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-ia32-cdboot` | Red Hat:enterprise_linux:7::computenode | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-x64-cdboot` | Red Hat:enterprise_linux:7::computenode | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc-modules` | Red Hat:enterprise_linux:7::computenode | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc64-modules` | Red Hat:enterprise_linux:7::computenode | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc64le-modules` | Red Hat:enterprise_linux:7::computenode | All versions | 1:2.02-0.87.el7_9.11 | | `grub2` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-common` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-debuginfo` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-aa64-modules` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-ia32` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-ia32-cdboot` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-ia32-modules` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-x64` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-x64-cdboot` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-efi-x64-modules` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-pc` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-pc-modules` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc-modules` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc64` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | | `grub2-ppc64-modules` | Red Hat:enterprise_linux:7::server | All versions | 1:2.02-0.87.el7_9.11 | Products: Gnu Grub2. ## How do I fix CVE-2022-28733? Apply the vendor's patch. ## Is CVE-2022-28733 being exploited? There is no known exploitation of CVE-2022-28733 in the wild and no public exploit code. ## Other vulnerabilities in GNU GRUB - [CVE-2024-56737](https://insights.sbomify.com/CVE-2024-56737/): Memory corruption in GRUB2 (high 8.8) - [CVE-2022-28734](https://insights.sbomify.com/CVE-2022-28734/): Out-of-bounds write when handling split HTTP headers (high 8.1) - [CVE-2025-61662](https://insights.sbomify.com/CVE-2025-61662/): Grub2: missing unregister call for gettext command may lead to use-after-free (high 7.8) - [CVE-2024-45782](https://insights.sbomify.com/CVE-2024-45782/): Grub2: fs/hfs: strcpy() using the volume name (fs/hfs.c:382) (high 7.8) - [CVE-2025-0678](https://insights.sbomify.com/CVE-2025-0678/): Grub2: squash4: integer overflow may lead to heap based out-of-bounds write when reading data (high 7.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2022-28733 and fix it if it is affected. What it is: CVE-2022-28733 is a high-severity vulnerability in GNU GRUB, published on 20 Jul 2023. 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-2022-28733 in the wild and no public exploit code. Affected product: GNU GRUB. 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-2022-28733/ (Markdown: https://insights.sbomify.com/CVE-2022-28733/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2022-28733 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-28733 - OSV: https://osv.dev/vulnerability/CVE-2022-28733 --- From sbomify Insights: https://insights.sbomify.com/CVE-2022-28733/ Summaries are generated and may contain mistakes; the official description above is the record.