# CVE-2021-33515: Command injection in n/a > Attackers can inject commands via STARTTLS in Dovecot's submission service to redirect sensitive information to attacker-controlled addresses. - **Severity:** Medium 4.8 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 28 Jun 2021 - **Updated:** 3 Aug 2024 - **Also known as:** ALPINE-CVE-2021-33515, ALSA-2022:1950, AZL-7196, CLSA-2022-1653506138, CLSA-2022-1653506545, DEBIAN-CVE-2021-33515, GHSA-pwmq-cvcm-r5p2, RHSA-2022:1950, RLSA-2022:1950, UBUNTU-CVE-2021-33515, USN-4993-1 ## What is CVE-2021-33515? CVE-2021-33515 is a medium-severity command injection vulnerability in Debian Debian Linux, published on 28 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description The submission service in Dovecot before 2.3.15 allows STARTTLS command injection in lib-smtp. Sensitive information can be redirected to an attacker-controlled address. Weakness: CWE-77 (Improper Neutralization of Special Elements used in a Command) ## Which versions are affected by CVE-2021-33515? It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `dovecot` | AlmaLinux:8 | All versions | 1:2.3.16-2.el8 | | `dovecot-devel` | AlmaLinux:8 | All versions | 1:2.3.16-2.el8 | | `dovecot-mysql` | AlmaLinux:8 | All versions | 1:2.3.16-2.el8 | | `dovecot-pgsql` | AlmaLinux:8 | All versions | 1:2.3.16-2.el8 | | `dovecot-pigeonhole` | AlmaLinux:8 | All versions | 1:2.3.16-2.el8 | | `dovecot` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-debugsource` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-mysql` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-mysql-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-pgsql` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-pgsql-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-pigeonhole` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot-pigeonhole-debuginfo` | Red Hat:enterprise_linux:8::appstream | All versions | 1:2.3.16-2.el8 | | `dovecot` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.3.16-2.el8 | | `dovecot-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.3.16-2.el8 | | `dovecot-debugsource` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.3.16-2.el8 | | `dovecot-devel` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.3.16-2.el8 | | `dovecot-mysql-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.3.16-2.el8 | | `dovecot-pgsql-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.3.16-2.el8 | | `dovecot-pigeonhole-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:2.3.16-2.el8 | | `dovecot` | Rocky Linux:8 | All versions | 1:2.3.16-2.el8 | Products: Debian Debian Linux, Dovecot Dovecot, Fedoraproject Fedora. ## How do I fix CVE-2021-33515? Upgrade to a fixed version. ## Is CVE-2021-33515 being exploited? There is no known exploitation of CVE-2021-33515 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild) - [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild) - [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild) - [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild) - [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-33515 and fix it if it is affected. What it is: CVE-2021-33515 is a medium-severity command injection vulnerability in Debian Debian Linux, published on 28 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-2021-33515 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-2021-33515/ (Markdown: https://insights.sbomify.com/CVE-2021-33515/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-33515 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-33515 - OSV: https://osv.dev/vulnerability/CVE-2021-33515 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-33515/ Summaries are generated and may contain mistakes; the official description above is the record.