Cyber Resilience

CVE-2026-44893

Netty ≤ 4.1.135

Published
12 June 2026
Modified
12 August 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0062 46th percentile
Risk Priority 58 floored blend · peak EPSS

Summary

CVE-2026-44893 is a high-severity Improper Check or Handling of Exceptional Conditions (CWE-703) vulnerability in Netty Netty. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 46th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SC-24 (Fail in Known State) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-703CWE-805

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-42580Same product: Netty Netty
CVE-2026-42579Same product: Netty Netty
CVE-2026-48059Same product: Netty Netty
CVE-2026-59901Same product: Netty Netty
CVE-2026-42581Same product: Netty Netty
CVE-2025-58056Same product: Netty Netty
CVE-2026-33870Same product: Netty Netty
CVE-2026-42585Same product: Netty Netty
CVE-2026-42584Same product: Netty Netty
CVE-2026-50020Same product: Netty Netty

Affected Assets

netty
netty
≤ 4.1.135 · 4.2.0 — 4.2.15

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation (including fuzzing and static analysis) directly finds incorrect length values used in sequential buffer accesses.

SC-24 Fail in Known State good match

Enforces failure to a known state while preserving required properties, limiting impact of unhandled exceptions.

SI-17 Fail-safe Procedures good match

Mandates explicit fail-safe procedures triggered by indicated failures, structurally preventing unhandled exceptional conditions.

SA-8 Security and Privacy Engineering Principles partial match

Requires application of security engineering principles that include robust exception and error handling during design.

SI-10 Information Input Validation partial match

Input validation rejects or corrects malformed length values supplied from external sources before they reach buffer operations.

SI-11 Error Handling partial match

Requires generation of safe, actionable error messages that directly addresses proper handling of exceptional conditions.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices explicitly require anticipating and correctly handling exceptional conditions during design and coding.

ID.RA-01 partial match
prevents

Vulnerability identification can discover buffer-length flaws but does not prevent their introduction.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect out-of-bounds accesses, but does not guarantee prevention.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates buffer-safety practices that directly prevent incorrect length values.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify buffer-size validation, but do not prescribe implementation details.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage bounds-checked APIs, yet leave concrete coding decisions to developers.

A.8.28 Secure coding partial match
prevents

Secure coding explicitly requires correct buffer-length handling, eliminating CWE-805 when followed.

A.6.8 Information security event reporting none match
none

Reporting of unhandled errors or exceptional conditions surfaces latent failure paths so they can be corrected before exploitation.

References