CVE-2026-102479
8.7HighPublished 14 Oct 2026 · NVD status: Undergoing Analysis · AI triage by gemini-3.8-flash
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Impact
- High impact on integrity
- Weakness
- CWE-444
Impact
Remote, unauthenticated attackers can smuggle HTTP requests through reverse proxies to bypass security controls or poison caches. They only need network access to send specially crafted HTTP/1.x headers.
Root cause
The HTTP/1.x decoder flawed header canonicalization erroneously matches malformed headers like Content-Xength to standard headers such as Content-Length.
Affected systems
io.vertx:vertx-core versions 5.0.0 through 5.0.12, 5.1.0 through 5.1.9, and 5.2.0
CVSS v4.0 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Fix & remediation
Upgrade io.vertx:vertx-core to versions beyond 5.0.12, 5.1.9, or 5.2.0 (check the advisory for exact patch releases). As an interim mitigation, configure your upstream reverse proxy or WAF to strictly reject non-standard or malformed HTTP header names.
$ ./mvnw dependency:tree -Dincludes=io.vertx:vertx-coreAI-suggested. Run it in staging first and check it against the vendor advisory. Why?
NVD description
In Eclipse Vert.x versions [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the Vert.x HTTP/1.x decoder uses a canonicalization for well known HTTP headers, the canonicalization process interprets well crafted headers as headers of this list, allowing for instance Content-Xength to be interpeted as Content-Length. This can be exploited for request smuggling purpose. The impacted component is io.vertx:vertx-core.