# CVE-2026-44893: netty-codec — Fixed in 4.2.15.Final ☕ ☕ Maven Not in CISA KEV HIGH severity # CVE-2026-44893 — netty-codec-haproxy HIGH CVE-2026-44893 is a high-severity (CVSS 7.5) CWE-703 vulnerability in io.netty:netty-codec-haproxy. A fix is available for io.netty:netty-codec-haproxy — see the affected versions and patch details below. Netty: HAProxy SSL TLV parsing leaks retained slice on invalid TLV length Also known as[GHSA-cc37-9q2j-3hfv](/vulnerability/GHSA-cc37-9q2j-3hfv) Published Jun 12, 2026 Updated Oct 28, 2026 Affected 2 pkgs Patched 2 / 2 Exploits None indexed Exploitation data as of Nov 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS) ## Exploitation Status ### No confirmed exploitation observed yet - CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks. - CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment. Exploitation and automatability from CISA’s SSVC triage for CVE-2026-44893. ## EPSS Exploitation Probability [via FIRST.org ↗](https://www.first.org/epss/) 0.6%probability of exploitation in next 30 days Lower Risk0.00% Lower risk than most CVEs50th percentile — riskier than 50% of all scored CVEsHighest risk 0.08%0.51%0.95%1.38%0.6%0.6%Jul 26Oct 26Nov 26 Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/). ## How urgent is this, really ## Where this sits among everything scored ## Real-World Exposure 2 pkgs affected ☕`io.netty:netty-codec-haproxy`☕`io.netty:netty-codec-haproxy` Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems. ## Description Netty is a network application framework for development of protocol servers and clients. In netty-codec-haproxy prior to versions 4.1.135.Final and 4.2.15.Final, when decoding a PP2\_TYPE\_SSL TLV, HAProxyMessage.readNextTLV() first calls `header.retainedSlice(header.readerIndex(), length)` and only then reads the 1-byte client field and 4-byte verify field. If the attacker sets the TLV length below 5, the subsequent readByte/readInt throws IndexOutOfBoundsException. HAProxyMessageDecoder only catches HAProxyProtocolException around this call, so the IOOBE propagates and the retained slice on the pooled cumulation buffer is never released. Versions 4.1.135.Final and 4.2.15.Final patch the issue. ## Affected Packages 2 total 2 fixed Ecosystem Package Vulnerable range Fix ☕Maven `io.netty:netty-codec-haproxy` ≥ 4.2.0.Final&&< 4.2.15.Final 4.2.15.Final`io.netty:netty-codec-haproxy:4.2.15.Final` ☕Maven `io.netty:netty-codec-haproxy` all versions 4.1.135.Final`io.netty:netty-codec-haproxy:4.1.135.Final` ## Affected Products 1 product · 2 configurations Application `netty`netty ≥ 4.2.0 && < 4.2.15 range ## Detection & mitigation playbook Open-source dependency 1. ### Detect Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.netty:netty-codec-haproxy, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version. 2. ### Fix Update io.netty:netty-codec-haproxy to 4.2.15.Final or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-44893 is resolved across your whole dependency graph. 3. ### Workarounds If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. ## Fixing This On Your OS If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project. Red HatImportant This flaw is rated as Important because a remote, unauthenticated attacker can trigger a denial of service in applications utilizing \`netty-codec-haproxy\`. By sending a specially crafted HAProxy message with a malformed SSL TLV header, an attacker can cause an \`IndexOutOfBoundsException\`, leading to unreleased memory… Workaround published by Red Hat > Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. Source: [Red Hat security advisory for CVE-2026-44893](https://access.redhat.com/security/cve/cve-2026-44893) (CC BY 4.0) Product Fixed in Advisory Cryostat 4 on RHEL 9 `cryostat/cryostat-reports-rhel9:4.2.0-13` [RHSA-2026:48151](https://access.redhat.com/errata/RHSA-2026:48151) Red Hat AMQ Broker 7.14.1 `netty-codec-haproxy` [RHSA-2026:66488](https://access.redhat.com/errata/RHSA-2026:66488) Red Hat Build of Apache Camel 3.33.2.SP1 `io.netty/netty-codec-haproxy:4.1.135.Final-redhat-00001` [RHSA-2026:26586](https://access.redhat.com/errata/RHSA-2026:26586) Red Hat build of Apache Camel 4.18.1.P1 for Spring Boot 3.5.16 `netty-codec-haproxy` [RHSA-2026:37390](https://access.redhat.com/errata/RHSA-2026:37390) Red Hat build of Keycloak 26.4.13 see advisory [RHSA-2026:30049](https://access.redhat.com/errata/RHSA-2026:30049) Red Hat build of Keycloak 26.6.4 see advisory [RHSA-2026:30083](https://access.redhat.com/errata/RHSA-2026:30083) Red Hat build of Quarkus 3.27.4.SP1 `io.netty/netty-codec-haproxy:4.1.135.Final-redhat-00001` [RHSA-2026:26018](https://access.redhat.com/errata/RHSA-2026:26018) Red Hat build of Quarkus 3.33.2.SP1 `io.netty/netty-codec-haproxy:4.1.135.Final-redhat-00001` [RHSA-2026:26017](https://access.redhat.com/errata/RHSA-2026:26017) ## Frequently Asked Questions Netty is a network application framework for development of protocol servers and clients. In netty-codec-haproxy prior to versions 4.1.135.Final and 4.2.15.Final, when decoding a PP2\_TYPE\_SSL TLV, HAProxyMessage.readNextTLV() first calls \`header.retainedSlice(header.readerIndex(), length)\` and only then reads the 1-byte client field and 4-byte verify field. If the attacker sets the TLV length below 5, the subsequent readByte/readInt throws IndexOutOfBoundsException. HAProxyMessageDecoder only catches HAProxyProtocolException around this call, so the IOOBE propagates and the retained slice on t O3 Security · Impact-Aware SCA ### Is CVE-2026-44893 in your dependencies? Find it across Maven, including transitive dependencies. [Scan my dependencies](/book-demo) [How O3 SCA works](/impact-aware-sca)