CVE-2026-44891 | Netty: Denial of Service via Unbounded Headers in StompSubframeDecoder

Exp

Netty is a network application framework for development of protocol servers and clients. Prior to 4.1.136.Final and 4.2.16.Final, io.netty.handler.codec.stomp.StompSubframeDecoder fails to limit the total number of headers or their cumulative size per frame, and the maxLineLength parameter only restricts individual header lines. An attacker can send a large number of short headers that are accumulated in memory inside DefaultStompHeadersSubframe until the JVM throws an OutOfMemoryError, causing denial of service for servers exposing a STOMP endpoint based on StompSubframeDecoder. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Published: 2026-07-17 Last update: 2026-07-22 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-44891 is rated High Exploit Risk (62/100): CVSS High severity, with low exploitation likelihood (EPSS 0.69%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-44891

EDB-ID Source Kind Published Link
nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-44891

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-18 0.69%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-44891

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.9 3.6 [email protected]

Weakness enumeration for CVE-2026-44891

GitHub Security Advisory for CVE-2026-44891

GHSA-vhch-2wf3-m8rp · Severity: high · Ecosystem: maven — Netty: Denial of Service via Unbounded Headers in StompSubframeDecoder

OS Trackers for CVE-2026-44891

vendor priority summary link
debian not yet assigned CVE-2026-44891 not yet assigned priority: Debian including 1 source packages (netty), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2026-44891
suse high CVE-2026-44891 severity important: SUSE including 2 source package names (netty-tcnative, netty3), 24 product×package rows across 12 product lines (SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS, … (12 product lines)): Known Not Affected 24. https://www.suse.com/security/cve/CVE-2026-44891/
ubuntu medium CVE-2026-44891 medium priority: Ubuntu including 1 source packages (netty), 7 status rows across 7 suites (bionic, focal, jammy, noble, resolute, trusty, upstream): needs-triage 7. https://ubuntu.com/security/CVE-2026-44891

Affected software / configurations for CVE-2026-44891

Vendor Product Version Raw CPE
netty netty < 4.1.136 cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
netty netty >= 4.2.0, <= 4.2.16 cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

References for CVE-2026-44891

cvelogic Threat Intelligence