CVE-2018-12541

In version from 3.0.0 to 3.5.3 of Eclipse Vert.x, the WebSocket HTTP upgrade implementation buffers the full http request before doing the handshake, holding the entire request body in memory. There should be a reasonnable limit (8192 bytes) above which the WebSocket gets an HTTP response with the 413 status code and the connection gets closed.

Published: 2018-10-10 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2018-12541 is rated Moderate Risk (56.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.65%). Core evidence: EPSS rose +1.31% over the last day, indicating growing attacker interest. Mandatory action: Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2018-12541

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 2026-06-15 1.34% 2.65% +1.31%
2 2025-04-21 1.06% 1.34% +0.28%
3 2025-03-30 1.06%

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-12541

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/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:L)
A normal user session is enough; they don’t have to be admin.
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.
2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
8.0 2.9 [email protected]

Weakness enumeration for CVE-2018-12541

GitHub Security Advisory for CVE-2018-12541

OS Trackers for CVE-2018-12541

vendor priority summary link
redhat medium https://access.redhat.com/security/cve/CVE-2018-12541

Affected software / configurations for CVE-2018-12541

Vendor Product Version Raw CPE
eclipse vert.x >= 3.0.0, < 3.5.4 cpe:2.3:a:eclipse:vert.x:*:*:*:*:*:*:*:*

References for CVE-2018-12541

URL Tags
https://access.redhat.com/errata/RHSA-2018:2946 Third Party Advisory
https://bugs.eclipse.org/bugs/show_bug.cgi?id=539170 Vendor Advisory
https://github.com/eclipse-vertx/vert.x/issues/2648 Third Party Advisory
https://lists.apache.org/thread.html/r01123837ffbfdf5809e0a4ac354ad546e4ca8f18df89ee5a10eeb81b%40%3Cissues.bookkeeper.apache.org%3E
https://lists.apache.org/thread.html/r11789cd6d67ecca2d6f6bbb11e34495e68ee99287b6c59edf5b1a09c%40%3Ccommits.pulsar.apache.org%3E
https://lists.apache.org/thread.html/r1af71105539fe01fcecb92d2ecd8eea56c515fb1c80ecab4df424553%40%3Cissues.bookkeeper.apache.org%3E
https://lists.apache.org/thread.html/r344235b1aea2f7fa2381495df1d77d02b595e3d7e4626e701f7c1062%40%3Ccommits.pulsar.apache.org%3E
https://lists.apache.org/thread.html/r362835e6c7f34324ed24e318b363fcdd20cea91d0cea0b2e1164f73e%40%3Cissues.bookkeeper.apache.org%3E
https://lists.apache.org/thread.html/r3da899890536af744dec897fbc561fd9810ac45e79a16164b53c31b2%40%3Ccommits.pulsar.apache.org%3E
https://lists.apache.org/thread.html/r79789a0afb184abd13a2c07016e6e7ab8e64331f332b630bf82a2eed%40%3Ccommits.pulsar.apache.org%3E
https://lists.apache.org/thread.html/r8db0431ecf93f2dd2128db5ddca897b33ba883b7f126648d6a9e4c47%40%3Ccommits.pulsar.apache.org%3E
https://lists.apache.org/thread.html/r98dc06e2b1c498d0e9eb5038d8e1aefd24e411e50522e7082dd9e0b7%40%3Ccommits.bookkeeper.apache.org%3E
https://lists.apache.org/thread.html/rbdc279ecdb7ac496a03befb05a53605c4ce2b67e14f8f4df4cfa1203%40%3Cissues.bookkeeper.apache.org%3E
https://lists.apache.org/thread.html/rd0e44e8ef71eeaaa3cf3d1b8b41eb25894372e2995ec908ce7624d26%40%3Ccommits.pulsar.apache.org%3E
https://lists.apache.org/thread.html/re5ddabee26fbcadc7254d03a5a073d64080a9389adc9e452529664ed%40%3Ccommits.pulsar.apache.org%3E
https://lists.apache.org/thread.html/reb3cc4f3e10264896a541813c0030ec9d9466ba9b722fe5d4adc91cd%40%3Cissues.bookkeeper.apache.org%3E
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