CVE-2026-91920— Undertow: undertow: chunkreader message length permits chunk-size overflow
Quick assessment
Affected
Red Hat Red Hat build of Apache Camel for Spring Boot 4
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Undertow Web 服务器的 ChunkReader 组件中发现了一个漏洞，该组件用于处理 HTTP 请求中的分块传输编码（chunked transfer encoding）。该问题源于在数值进行位移操作之前执行了分块大小的安全检查，这使得攻击者可以构造一个特定的 15 位分块大小，从而绕过限制并导致内部状态标志位发生溢出。此漏洞可能导致服务器过早终止请求体，并将剩余数据解释为一条被“走私”（smuggled）的独立请求。
Possible ATT&CK Techniques 2 AI
T1055.004 · Asynchronous Procedure Call T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-91920
Vulnerability Information
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Vulnerability Title
Undertow: undertow: chunkreader message length permits chunk-size overflow
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
HTTP请求的解释不一致性(HTTP请求私运)
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Red Hat | Red Hat build of Apache Camel for Spring Boot 4 | - |
cpe:/a:redhat:camel_spring_boot:4
|
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| Red Hat | Red Hat Enterprise Linux 8 | - |
cpe:/o:redhat:enterprise_linux:8
|
|
| Red Hat | Red Hat Enterprise Linux 8 | - |
cpe:/o:redhat:enterprise_linux:8
|
|
| Red Hat | Red Hat Enterprise Linux 9 | - |
cpe:/o:redhat:enterprise_linux:9
|
|
| Red Hat | Red Hat Fuse 7 | - |
cpe:/a:redhat:jboss_fuse:7
|
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | - |
cpe:/a:redhat:jboss_enterprise_application_platform:7
|
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | - |
cpe:/a:redhat:jboss_enterprise_application_platform:7
|
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | - |
cpe:/a:redhat:jboss_enterprise_application_platform:7
|
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | - |
cpe:/a:redhat:jboss_enterprise_application_platform:7
|
|
| Red Hat | Red Hat JBoss Enterprise Application Platform 8 | - |
cpe:/a:redhat:jboss_enterprise_application_platform:8
|
|
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | - |
cpe:/a:redhat:jbosseapxp
|
|
| Red Hat | Red Hat Single Sign-On 7 | - |
cpe:/a:redhat:red_hat_single_sign_on:7
|
|
II. Public POCs for CVE-2026-91920
| # | POC Description | Source Link | Shenlong Link |
|---|
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Other References for CVE-2026-91920 (2)
Same Patch Batch · Red Hat · 2026-10-30 · 7 CVEs total
| CVE-2026-103963 | 7.5 HIGH | Glib-networking: unbounded tls 1.3 session ticket queue growth in glib-networking allows r |
| CVE-2026-110133 | 5.8 MEDIUM | Ghostscript: heap buffer overflow in ghostscript truetype outliner due to npointstotal int |
| CVE-2026-118959 | 5.4 MEDIUM | Keycloak-services: keycloak-services: required actions bypassed via kc_action parameter |
| CVE-2026-118947 | 4.3 MEDIUM | Keycloak-services: keycloak-services: authorization bypass via uma resource registration i |
| CVE-2026-118475 | 3.6 LOW | Eog: eye of gnome: buffer overrun when parsing malicious png files with non-standard iccp |
| CVE-2026-112922 | 3.3 LOW | Ghostscript: out-of-bounds read in ghostscript shade_next_color via integer overflow of in |
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Same product: Red Hat build of Apache Camel for Spring Boot 4
-
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Same vendor: Red Hat
-
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Eog: eye of gnome: buffer overrun when parsing malicious png -
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Same weakness: CWE-444
-
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Chunk extensions accept bare LF and CR, enabling request smu -
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CVE-2026-115877
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