Heap exhaustion via unbounded line accumulation in Vert.x STOMP FrameParser
Vert.x STOMP FrameParser in versions 4.0.0 to 4.5.35 and 5.0.0 to 5.2.2 lets a remote peer exhaust JVM heap by streaming bytes with no newline. Fixed in 4.5.36 and 5.2.3.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- Proof of concept public, per CISA
- Fix
- Fixed in 5.2.3, 4.5.36
- Who is exposed
- Default setups
Do first: Check every install: default setups are affected.
- Exploitation15/40CISA rates a proof of concept as public
- Exposure25/25Default setups, CISA rates it automatable
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity7.5/10CVSS 7.5
- No patch0/5No signal
What would change the score
- Would score about 73 if added to CISA KEV
- Would score about 68 if CISA's SSVC rates exploitation active
CVE-2026-118487 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects Eclipse Vert.x; fixed in 5.2.3 and 4.5.36.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 48/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Default setups
- Fix
- Fixed in 5.2.3, 4.5.36
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: yes
- Technical impact: partial
Summary
The vertx-stomp component of Eclipse Vert.x, which implements the STOMP messaging protocol for both servers and clients, is affected. A remote peer that keeps sending data without a line break can make the process consume all available Java heap memory, crashing it and denying service to its users.
Read the original description
In Eclipse Vert.x versions [4.0.0, 4.5.35] or [5.0.0, 5.2.2], the `FrameParser` in vertx-stomp creates a `RecordParser` without setting `maxRecordSize`, so any peer that streams bytes continuously without a newline character causes the parser to accumulate data indefinitely. Both the STOMP server and the STOMP client are affected: a malicious server can exploit this against a connecting client, and a malicious client can exploit this against a server before or after authentication. Sustained byte streaming exhausts JVM heap memory, crashing the affected process and causing a complete denial of service.
What to do
Check every install: default setups are affected.
Upgrade to a fixed version: 5.2.3, 4.5.36.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- Eclipse Foundation Eclipse Vert.x
From 4.0.0 · through 4.5.35; From 5.0.0 · through 5.2.2
Evidence 3
- Advisory
- Link
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-118487
Is CVE-2026-118487 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The STOMP frame parser keeps collecting incoming bytes while waiting for a newline character. A peer that sends a continuous stream without a newline makes the parser hold that data indefinitely, which can use up the JVM heap and crash the process.Source: github.com
Which versions are affected by CVE-2026-118487?
Eclipse Vert.x: from 4.0.0 through 4.5.35; from 5.0.0 through 5.2.2.Source: cve.now feed data
Am I affected, and how do I check?
Eclipse Vert.x versions 4.0.0 through 4.5.35 and 5.0.0 through 5.2.2 are affected. To check, look at the Vert.x version your application depends on, for example in your build file or the dependency tree, and see whether it falls in those ranges.Source: github.com
How do I fix CVE-2026-118487?
Upgrade to Vert.x 4.5.36 if you are on the 4.x line, or to 5.2.3 if you are on the 5.x line.Source: github.com