CVE-2026-32239
Medium
Description
Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, a negative Content-Length value was converted to unsigned, treating it as an impossibly large length instead. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in 1.4.0.
SeverityMedium
CVSS6.5
Exploit probability—
ProductCapnproto
PublishedMar 12, 2026
First seenMar 12, 2026
Weakness typeCWE-444CWE-444CWE-190Integer overflow
How to fix
Update
- capnproto capnproto1.4.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| capnproto capnproto | v < 1.4.0 | 1.4.0 |
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