AI Threat Alert
CVE-2024-1023: Vert.x: memory leak in HTTP client enables DoS
MEDIUM CISA: TRACK*Eclipse Vert.x's HTTP client leaks memory via Netty FastThreadLocal data structures whenever it opens connections to new hosts, and an attacker who can influence which hosts get connected to can accelerate that leak until the process exhausts memory. This is a pure availability issue (CVSS 3.1 6.5, AV:N/AC:L/PR:L/UI:N, C:N/I:N/A:H) — no data exposure, no code execution — and while EPSS places it in the top 25% of scored CVEs, the raw exploitation probability (1.65%) is still low, it is not in CISA KEV, there is no public exploit or Nuclei template, and CISA's own SSVC decision is TRACK-STAR (monitor, not scramble). The realistic risk concentrates on any Java backend built on vertx-core that lets an agent, proxy, or crawler direct outbound HTTP connections to attacker-influenced or arbitrary internet addresses, since that is exactly the trigger condition the advisory describes. Action: patch to the fixed vertx-core release referenced in Red Hat's errata train (RHSA-2024:1662 and the follow-on 2024:1706/2088/2833/3527/3989/4884 rebuilds), and until then watch heap/off-heap memory on services embedding the Vert.x HTTP client that accept or forward arbitrary destination URLs.
What systems are affected?
| Package | Ecosystem | Vulnerable Range | Patched |
|---|---|---|---|
| cryostat-tech-preview/cryostat-grafana-dashboard-rhel8 | — | — | No patch |
| cryostat-tech-preview/cryostat-operator-bundle | — | — | No patch |
| cryostat-tech-preview/cryostat-reports-rhel8 | — | — | No patch |
| cryostat-tech-preview/cryostat-rhel8 | — | — | No patch |
| cryostat-tech-preview/cryostat-rhel8-operator | — | — | No patch |
| cryostat-tech-preview/jfr-datasource-rhel8 | — | — | No patch |
| io.vertx/vertx-core | — | — | No patch |
| mta/mta-windup-addon-rhel9 | — | — | No patch |
| vert.x | — | — | No patch |
| vertx-core | — | — | No patch |
How severe is it?
What is the attack surface?
What should I do?
No patch available
Monitor for updates. Consider compensating controls or temporary mitigations.
What does CISA's SSVC say?
Source: CISA Vulnrichment (SSVC v2.0). Decision based on the CISA Coordinator decision tree.
How is it classified?
Which compliance frameworks are affected?
Compliance analysis pending. Sign in for full compliance mapping when available.
Frequently Asked Questions
What is CVE-2024-1023?
Eclipse Vert.x's HTTP client leaks memory via Netty FastThreadLocal data structures whenever it opens connections to new hosts, and an attacker who can influence which hosts get connected to can accelerate that leak until the process exhausts memory. This is a pure availability issue (CVSS 3.1 6.5, AV:N/AC:L/PR:L/UI:N, C:N/I:N/A:H) — no data exposure, no code execution — and while EPSS places it in the top 25% of scored CVEs, the raw exploitation probability (1.65%) is still low, it is not in CISA KEV, there is no public exploit or Nuclei template, and CISA's own SSVC decision is TRACK-STAR (monitor, not scramble). The realistic risk concentrates on any Java backend built on vertx-core that lets an agent, proxy, or crawler direct outbound HTTP connections to attacker-influenced or arbitrary internet addresses, since that is exactly the trigger condition the advisory describes. Action: patch to the fixed vertx-core release referenced in Red Hat's errata train (RHSA-2024:1662 and the follow-on 2024:1706/2088/2833/3527/3989/4884 rebuilds), and until then watch heap/off-heap memory on services embedding the Vert.x HTTP client that accept or forward arbitrary destination URLs.
Is CVE-2024-1023 actively exploited?
No confirmed active exploitation of CVE-2024-1023 has been reported, but organizations should still patch proactively.
How to fix CVE-2024-1023?
No patch is currently available. Monitor vendor advisories for updates.
What is the CVSS score for CVE-2024-1023?
CVE-2024-1023 has a CVSS v3.1 base score of 6.5 (MEDIUM). The EPSS exploitation probability is 1.65%.
What are the technical details?
Original Advisory
A vulnerability in the Eclipse Vert.x toolkit results in a memory leak due to using Netty FastThreadLocal data structures. Specifically, when the Vert.x HTTP client establishes connections to different hosts, triggering the memory leak. The leak can be accelerated with intimate runtime knowledge, allowing an attacker to exploit this vulnerability. For instance, a server accepting arbitrary internet addresses could serve as an attack vector by connecting to these addresses, thereby accelerating the memory leak.
Weaknesses (CWE)
CWE-401 — Missing Release of Memory after Effective Lifetime: The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
- [Implementation] Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391]. To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.
- [Architecture and Design] Use an abstraction library to abstract away risky APIs. Not a complete solution.
Source: MITRE CWE corpus.
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H References
- access.redhat.com/errata/RHSA-2024:1662 vendor-advisory x_refsource_REDHAT
- access.redhat.com/errata/RHSA-2024:1706 vendor-advisory x_refsource_REDHAT
- access.redhat.com/errata/RHSA-2024:2088 vendor-advisory x_refsource_REDHAT
- access.redhat.com/errata/RHSA-2024:2833 vendor-advisory x_refsource_REDHAT
- access.redhat.com/errata/RHSA-2024:3527 vendor-advisory x_refsource_REDHAT
- access.redhat.com/errata/RHSA-2024:3989 vendor-advisory x_refsource_REDHAT
- access.redhat.com/errata/RHSA-2024:4884 vendor-advisory x_refsource_REDHAT
- access.redhat.com/security/cve/CVE-2024-1023 vdb-entry x_refsource_REDHAT
- bugzilla.redhat.com/show_bug.cgi issue-tracking x_refsource_REDHAT
- github.com/eclipse-vertx/vert.x/issues/5078
- github.com/eclipse-vertx/vert.x/pull/5080
- github.com/eclipse-vertx/vert.x/pull/5082