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HttpComponents Core EUVDEUVD-2026-41095

| CVE-2026-54428 HIGH
Uncontrolled Resource Consumption (CWE-400)
7.5
CVSS 3.1 · Vendor
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Severity by source

Vendor (CNA) PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
7.5 HIGH

Network-reachable, unauthenticated attack during HTTP/2 handshake; availability-only impact via heap exhaustion, no confidentiality or integrity effect.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
HIGH
qualitative
Red Hat
7.5 HIGH
qualitative

Primary rating from Vendor (CNA).

CVSS VectorVendor

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

2
CVSS changed
Jul 01, 2026 - 19:22 NVD
7.5 (HIGH)
Analysis Generated
Jul 01, 2026 - 16:16 vuln.today

Blast Radius

ecosystem impact
† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth
  • 1 maven packages depend on org.apache.httpcomponents.core5:httpcore5-h2 (1 direct, 0 indirect)

Ecosystem-wide dependent count for version 5.5-alpha1.

Description PRE-NVD

Disclosed via oss-security. NVD scoring and full description are pending.

AnalysisAI

Memory exhaustion denial-of-service in Apache HttpComponents Core's HTTP/2 HPACK decoder allows remote attackers to crash Java services by sending oversized compressed header blocks before the HTTP/2 SETTINGS acknowledgement is processed. The root cause is a timing gap in the connection handshake: the server's configured maximum header list size limit is not enforced until after the SETTINGS ACK exchange completes, leaving a window during which an attacker can flood the decoder with arbitrarily large compressed header data. Affected artifacts are org.apache.httpcomponents.core5:httpcore5-h2 versions 5.4.2 and earlier and 5.5-beta1 and earlier. No public exploit or CISA KEV listing has been identified at time of analysis.

Technical ContextAI

Apache HttpComponents Core (httpcore5-h2) is a low-level Java HTTP/2 transport library used as a foundational dependency in a broad range of Java server and client applications, including Apache projects and Spring-based stacks. HTTP/2 uses HPACK (RFC 7541) for header compression, which maintains a dynamic table and allows senders to reference previously seen headers in compressed form. The HTTP/2 SETTINGS frame (RFC 9113 §6.5) carries peer configuration including SETTINGS_MAX_HEADER_LIST_SIZE, which caps the total uncompressed size of a header list. Critically, the SETTINGS exchange involves a send-and-acknowledge cycle; the receiver must send a SETTINGS ACK to confirm it has processed the peer's parameters. This vulnerability (consistent with CWE-770: Allocation of Resources Without Limits or Throttling) arises because the HPackDecoder does not apply the configured header list size cap during this pre-ACK window. An attacker who initiates an HTTP/2 connection and immediately sends header blocks before the SETTINGS ACK is processed can cause unbounded heap allocation, leading to OutOfMemoryError and service-level denial of service.

RemediationAI

The primary remediation is to upgrade org.apache.httpcomponents.core5:httpcore5-h2 to a version that enforces the configured SETTINGS_MAX_HEADER_LIST_SIZE before the SETTINGS ACK completes. The advisory does not explicitly name a fixed release version in the provided data - the exact patched artifact version should be confirmed via the Apache HttpComponents release page at https://hc.apache.org/ and the oss-security advisory at https://seclists.org/oss-sec/2026/q3/2 before deploying. As a compensating control where an immediate upgrade is not possible, placing an HTTP/2-aware reverse proxy (such as nginx or HAProxy) in front of the affected service can apply connection-level header size limits before traffic reaches the Java application, reducing the attack surface with the trade-off of added infrastructure complexity. Additionally, applying JVM heap limits (-Xmx) and enabling crash restarts via a process supervisor will limit the blast radius of a successful exhaustion attempt but will not prevent transient service disruption. Disabling HTTP/2 entirely in the application configuration eliminates the vulnerable code path if HTTP/2 is not a business requirement, at the cost of losing multiplexing and header compression performance gains.

Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Not-Affected
SUSE Linux Enterprise High Performance Computing 15 SP7 Not-Affected
SUSE Linux Enterprise Module for Development Tools 15 SP7 Not-Affected
SUSE Linux Enterprise Server 15 SP7 Not-Affected
SUSE Linux Enterprise Server 16.0 Not-Affected

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EUVD-2026-41095 vulnerability details – vuln.today

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