How severe is CVE-2025-49574?

CVE-2025-49574 has a CVSS score of 6.4/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2025-49574?

CVE-2025-49574 affects the following packages: io.quarkus:quarkus-vertx (Maven), io.quarkus:quarkus-vertx (Maven), io.quarkus:quarkus-vertx (Maven). Ecosystems affected: Maven.

How do I fix CVE-2025-49574?

Update io.quarkus:quarkus-vertx to 3.15.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-49574 is resolved across your whole dependency graph.

How do I detect CVE-2025-49574 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.quarkus:quarkus-vertx, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-49574 if there is no patch (or I can't update yet)?

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.

Is CVE-2025-49574 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-49574 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-49574?

CVE-2025-49574 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 21th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-49574?

CVE-2025-49574 is classified as CWE-668 (CWE-668). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-49574 published, and has it been updated?

CVE-2025-49574 was published on June 23, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2025-49574 — quarkus-vertx

MEDIUMFix: quarkusio/quarkus@2b58f59

CVE-2025-49574 is a medium-severity (CVSS 6.4) CWE-668 vulnerability in io.quarkus:quarkus-vertx. A fix is available for io.quarkus:quarkus-vertx — see the affected versions and patch details below.

Quarkus potential data leak when duplicating a duplicated context

Also known asGHSA-9623-mj7j-p9v4

Published

Jun 23, 2025

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
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-2025-49574.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs21th percentile — riskier than 21% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

☕io.quarkus:quarkus-vertx☕io.quarkus:quarkus-vertx☕io.quarkus:quarkus-vertx

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

Impact

Vert.x 4.5.12 has changed the semantics of the duplication of duplicated context.

Duplicated context is an object used to propagate data through a processing (synchronous or asynchronous). Each "transaction" or "processing" runs on its own isolated duplicated context.

Initially, duplicating a duplicated context was creating a fresh (empty) new context, meaning that the new duplicated context can be used to managed a separated transaction.

In Vert.x 4.5.12, this semantics has changed, and since the content of the parent duplicated context is copied into the new one, potentially leaking data.

This CVE is especially for Quarkus as Quarkus extensively uses the Vert.x duplicated context to implement context propagation. With the new semantic data from one transaction can leak to the data from another transaction. From a Vert.x point of view, this new semantic clarifies the behavior.

A significant amount of data is stored in the duplicated context, including request scope, security details, and metadata. Duplicating a duplicated context is rather rare and is only done in a few places:

Quarkus REST Client when using OTel (but it's the same transaction, so no leak)
Quarkus Messaging connectors
Quarkus SmallRye Health (same transaction, so no leak)

Patches

After discussion with the Vert.x team, the change will be rolled back in Vert.x 4.x. A new API will be added to Vert.x 5 do distinguish the 2 cases.

Workarounds

When duplicating a duplicated context, the following code can be done to avoid the potential leak:

((ContextInternal) VertxContext.getRootContext(ctx)).duplicate()

This workaround would not be required once the Vert.x version containing the fix will be included. Note that the workaround would still work.

References

This issue have been reported in https://github.com/quarkusio/quarkus/issues/48227.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`io.quarkus:quarkus-vertx`	all versions	3.15.6`io.quarkus:quarkus-vertx:3.15.6`
☕Maven	`io.quarkus:quarkus-vertx`	≥ 3.16.0.CR1&&< 3.20.2	3.20.2`io.quarkus:quarkus-vertx:3.20.2`
☕Maven	`io.quarkus:quarkus-vertx`	≥ 3.21.0.CR1&&< 3.24.1	3.24.1`io.quarkus:quarkus-vertx:3.24.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.quarkus:quarkus-vertx, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.quarkus:quarkus-vertx to 3.15.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-49574 is resolved across your whole dependency graph.
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 HatModerate

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-2025-49574 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat build of Quarkus 3.15.6	`quarkus-bom`	RHSA-2025:13012
Red Hat build of Quarkus 3.20.2.redhat	`io.quarkus/quarkus-vertx:3.20.2.redhat-00003`	RHSA-2025:13010
Streams for Apache Kafka 3.0.0	see advisory	RHSA-2025:12511
Streams for Apache Kafka 3.1.0	`quarkus-vertx`	RHSA-2025:23417

Frequently Asked Questions

### Impact Vert.x 4.5.12 has changed the semantics of the duplication of duplicated context. Duplicated context is an object used to propagate data through a processing (synchronous or asynchronous). Each "transaction" or "processing" runs on its own isolated duplicated context. Initially, duplicating a duplicated context was creating a fresh (empty) new context, meaning that the new duplicated context can be used to managed a separated transaction. In Vert.x 4.5.12, this semantics has changed, and since the content of the parent duplicated context is copied into the new one, potentially l