Undertow: undertow: chunkreader message length permits chunk-size overflow
CVSS score
6.5
EPSS probability
—
Risk score
0.7
Published
2 h ago
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Vulnerability description
DayBreach AI Explanation
Verified against sourcesSources read
1
Source agreement
Tam uyum
Evidence confidence
%53
Short explanation
A vulnerability exists in the ChunkReader component of the Undertow web server when handling chunked transfer encoding in HTTP requests. Because the security check for the chunk size occurs before the value is shifted, a crafted 15-digit chunk size can bypass the limit and overflow internal state flags.
This flaw allows the server to terminate a request body prematurely and interpret remaining data as a separate, smuggled request, potentially impacting system integrity and availability.
What should be done?
- Follow vendor advisories for affected product builds
- Monitor official channels for patch availability and status updates
The sources give limited detail on some technical conditions. Review the chain of evidence below before deciding how to act.
Chain of evidence and sources
CVE-2026-91920, Undertow web sunucusunun ChunkReader bileşenini etkiler.
Güvenlik kontrolünün kaydırma işleminden önce yapılması 15 haneli yığın boyutunun taşmasına yol açar.
Zafiyet, istek gövdesinin erken sonlandırılmasına ve kalan verilerin ayrı istek olarak yorumlanmasına neden olabilir.
Show the technical text from the sources
A flaw was found in the ChunkReader component of the Undertow web server, which is used to handle chunked transfer encoding in HTTP requests. The issue occurs because a security check for the chunk size is performed before the value is shifted, allowing a specifically crafted 15-digit chunk size to bypass the limit and overflow into internal state flags. This can cause the server to terminate a request body prematurely and interpret the remaining data as a separate, smuggled request.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
CWE: CWE-444
This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-91920 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | Red Hat | Red Hat build of Apache Camel for Spring Boot 4 | View |
| 2 | Red Hat | Red Hat Enterprise Linux 8 | View |
| 3 | Red Hat | Red Hat Enterprise Linux 9 | View |
| 4 | Red Hat | Red Hat Fuse 7 | View |
| 5 | Red Hat | Red Hat JBoss Enterprise Application Platform 7 | View |
| 6 | Red Hat | Red Hat JBoss Enterprise Application Platform 8 | View |
| 7 | Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | View |
| 8 | Red Hat | Red Hat Single Sign-On 7 | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 6.5 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L | CVE CNA |
| 6.5 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-91920 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-91920 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
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