# CVE-2010-4344: Exim Heap-Based Buffer Overflow > Remote attackers can execute arbitrary code on Exim mail servers via a heap-based buffer overflow triggered by crafted SMTP sessions. - **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Yes, since 25 Mar 2022 (CISA KEV) - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 14 Dec 2010 - **Updated:** 22 Oct 2025 - **Also known as:** DEBIAN-CVE-2010-4344, DSA-2131-1, GHSA-mvgg-qcrq-7wr8, RHSA-2010:0970 ## What is CVE-2010-4344? CVE-2010-4344 is a critical memory corruption vulnerability in Canonical Ubuntu Linux, published on 14 Dec 2010. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Heap-based buffer overflow in the string_vformat function in string.c in Exim before 4.70 allows remote attackers to execute arbitrary code via an SMTP session that includes two MAIL commands in conjunction with a large message containing crafted headers, leading to improper rejection logging. Weakness: CWE-787 (Out-of-bounds Write) ## Which versions are affected by CVE-2010-4344? It affects 4 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `exim` | Red Hat:enterprise_linux:4::as | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-debuginfo` | Red Hat:enterprise_linux:4::as | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-doc` | Red Hat:enterprise_linux:4::as | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-mon` | Red Hat:enterprise_linux:4::as | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-sa` | Red Hat:enterprise_linux:4::as | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-debuginfo` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-doc` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-mon` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-sa` | Red Hat:enterprise_linux:4::desktop | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim` | Red Hat:enterprise_linux:4::es | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-debuginfo` | Red Hat:enterprise_linux:4::es | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-doc` | Red Hat:enterprise_linux:4::es | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-mon` | Red Hat:enterprise_linux:4::es | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-sa` | Red Hat:enterprise_linux:4::es | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-debuginfo` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-doc` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-mon` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim-sa` | Red Hat:enterprise_linux:4::ws | All versions | 0:4.43-1.RHEL4.5.el4_8.1 | | `exim` | Red Hat:enterprise_linux:5::client | All versions | 0:4.63-5.el5_5.2 | | `exim-debuginfo` | Red Hat:enterprise_linux:5::client | All versions | 0:4.63-5.el5_5.2 | | `exim-mon` | Red Hat:enterprise_linux:5::client | All versions | 0:4.63-5.el5_5.2 | | `exim-sa` | Red Hat:enterprise_linux:5::client | All versions | 0:4.63-5.el5_5.2 | | `exim` | Red Hat:enterprise_linux:5::server | All versions | 0:4.63-5.el5_5.2 | | `exim-debuginfo` | Red Hat:enterprise_linux:5::server | All versions | 0:4.63-5.el5_5.2 | | `exim-mon` | Red Hat:enterprise_linux:5::server | All versions | 0:4.63-5.el5_5.2 | | `exim-sa` | Red Hat:enterprise_linux:5::server | All versions | 0:4.63-5.el5_5.2 | | `exim` | Red Hat:rhel_eus:4.7::as | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-debuginfo` | Red Hat:rhel_eus:4.7::as | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-doc` | Red Hat:rhel_eus:4.7::as | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-mon` | Red Hat:rhel_eus:4.7::as | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-sa` | Red Hat:rhel_eus:4.7::as | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim` | Red Hat:rhel_eus:4.7::es | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-debuginfo` | Red Hat:rhel_eus:4.7::es | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-doc` | Red Hat:rhel_eus:4.7::es | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-mon` | Red Hat:rhel_eus:4.7::es | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim-sa` | Red Hat:rhel_eus:4.7::es | All versions | 0:4.43-1.RHEL4.5.el4_7.1 | | `exim` | Red Hat:rhel_eus:5.3 | All versions | 0:4.63-3.el5_3.1 | | `exim-debuginfo` | Red Hat:rhel_eus:5.3 | All versions | 0:4.63-3.el5_3.1 | Products: Canonical Ubuntu Linux, Debian Debian Linux, Exim Exim, Opensuse Opensuse. ## How do I fix CVE-2010-4344? Upgrade to a fixed version. US federal agencies must fix it by 15 Apr 2022. ## Is CVE-2010-4344 being exploited? Yes. Attackers have exploited CVE-2010-4344 in the wild since at least 25 Mar 2022. Public exploit code: - Exim4 string_format Function Heap Buffer Overflow (metasploit) - Exim 4.63 - Remote Command Execution (exploitdb) - Exim4 < 4.69 - string_format Function Heap Buffer Overflow (Metasploit) (exploitdb) ## Other vulnerabilities in Canonical Ubuntu Linux - [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild) - [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2010-4344 and fix it if it is affected. What it is: CVE-2010-4344 is a critical memory corruption vulnerability in Canonical Ubuntu Linux, published on 14 Dec 2010. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: Yes. Attackers have exploited CVE-2010-4344 in the wild since at least 25 Mar 2022. Affected product: Canonical Ubuntu 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-2010-4344/ (Markdown: https://insights.sbomify.com/CVE-2010-4344/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2010-4344 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2010-4344 - OSV: https://osv.dev/vulnerability/CVE-2010-4344 --- From sbomify Insights: https://insights.sbomify.com/CVE-2010-4344/ Summaries are generated and may contain mistakes; the official description above is the record.