# CVE-2025-59419: Netty netty-codec-smtp SMTP Command Injection Vulnerability Allowing Email Forgery > Attackers can inject SMTP commands via CRLF characters to forge emails from trusted servers, bypassing SPF/DKIM checks. - **Severity:** Medium 5.5 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 15 Oct 2025 - **Updated:** 17 Oct 2025 - **Also known as:** CLEANSTART-2026-FZ71695, CLEANSTART-2026-MB73363, DEBIAN-CVE-2025-59419, GHSA-jq43-27x9-3v86, MINI-499w-vfx7-7cg6, MINI-4ww5-wq95-r878, MINI-gmhh-42gg-vq92, OESA-2025-2526, OESA-2025-2527, OESA-2025-2528, OESA-2025-2529, OESA-2025-2530, OESA-2025-2546, RHLW-2026-fb860419f051aedd, ROOT-APP-MAVEN-CVE-2025-59419, SUSE-SU-2025:4087-1, UBUNTU-CVE-2025-59419, USN-7843-1, openSUSE-SU-2025:15667-1 ## What is CVE-2025-59419? CVE-2025-59419 is a medium-severity command injection vulnerability in netty, published on 15 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.128.Final and 4.2.7.Final, the SMTP codec in Netty contains an SMTP command injection vulnerability due to insufficient input validation for Carriage Return (\r) and Line Feed (\n) characters in user-supplied parameters. The vulnerability exists in io.netty.handler.codec.smtp.DefaultSmtpRequest, where parameters are directly concatenated into the SMTP command string without sanitization. When methods such as SmtpRequests.rcpt(recipient) are called with a malicious string containing CRLF sequences, attackers can inject arbitrary SMTP commands. Because the injected commands are sent from the server's trusted IP address, resulting emails will likely pass SPF and DKIM authentication checks, making them appear legitimate. This allows remote attackers who can control SMTP command parameters (such as email recipients) to forge arbitrary emails from the trusted server, potentially impersonating executives and forging high-stakes corporate communications. This issue has been patched in versions 4.1.129.Final and 4.2.8.Final. No known workarounds exist. Weakness: CWE-93 (Improper Neutralization of CRLF Sequences) ## Which versions are affected by CVE-2025-59419? 4 open source packages ship an affected version, including io.netty:netty-codec-smtp. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `io.netty:netty-codec-smtp` | Maven | All versions | 4.1.128.Final | | `io.netty:netty-codec-smtp` | Maven | All versions | 4.1.128.Final | | `io.netty:netty-codec-smtp` | Maven | From 4.2.0.Alpha1 | 4.2.7.Final | | `io.netty:netty-codec-smtp` | Maven | From 4.2.0.Alpha1 | 4.2.7.Final | | `netty-tcnative` | SUSE:Linux Enterprise Module for Development Tools 15 SP6 | All versions | 2.0.74-150200.3.33.1 | | `netty-tcnative` | SUSE:Linux Enterprise Module for Development Tools 15 SP7 | All versions | 2.0.74-150200.3.33.1 | | `netty` | SUSE:Linux Enterprise Module for Package Hub 15 SP6 | All versions | 4.1.128-150200.4.37.1 | | `netty` | SUSE:Linux Enterprise Module for Package Hub 15 SP7 | All versions | 4.1.128-150200.4.37.1 | | `netty` | openSUSE:Leap 15.6 | All versions | 4.1.128-150200.4.37.1 | | `netty-tcnative` | openSUSE:Leap 15.6 | All versions | 2.0.74-150200.3.33.1 | | `netty` | openSUSE:Tumbleweed | All versions | 4.1.128-1.1 | ## How do I fix CVE-2025-59419? Upgrade io.netty:netty-codec-smtp to a fixed version for your release line: 4.1.128.Final or 4.2.7.Final. ## Is CVE-2025-59419 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-59419 exists. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2025-59419 and fix it if it is affected. What it is: CVE-2025-59419 is a medium-severity command injection vulnerability in netty, published on 15 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-59419 exists. Affected packages and fixed versions: - io.netty:netty-codec-smtp (Maven): affected all versions; fixed in 4.1.128.Final - io.netty:netty-codec-smtp (Maven): affected all versions; fixed in 4.1.128.Final - io.netty:netty-codec-smtp (Maven): affected from 4.2.0.Alpha1; fixed in 4.2.7.Final - io.netty:netty-codec-smtp (Maven): affected from 4.2.0.Alpha1; fixed in 4.2.7.Final 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-2025-59419/ (Markdown: https://insights.sbomify.com/CVE-2025-59419/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-59419 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-59419 - OSV: https://osv.dev/vulnerability/CVE-2025-59419 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-59419/ Summaries are generated and may contain mistakes; the official description above is the record.