Is CVE-2026-32240 in the CISA KEV catalog?

No. CVE-2026-32240 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-32240?

CVE-2026-32240 has a CVSS v3 base score of 6.5 (MEDIUM).

What is the EPSS score for CVE-2026-32240?

CVE-2026-32240 has an EPSS score of 0.21% (11th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-32240?

Upgrade capnproto on debian unstable to 1.4.0-2 or later.

CVE & CISA-KEV Catalog

CVE-2026-32240

MEDIUM

6.5

CVSS v3

NVD

Description

Cap'n Proto is a data interchange format and capability-based RPC system. Prior to 1.4.0, when using Transfer-Encoding: chunked, if a chunk's size parsed to a value of 2^64 or larger, it would be truncated to a 64-bit integer. In theory, this bug could enable HTTP request/response smuggling. This vulnerability is fixed in 1.4.0.

CWE-197 CWE-444

How to fix

Remediation Available

capnprotoDebian

Fixed in:1.4.0-2CVE-2026-32240

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Exploit Intelligence

0.21%probability of exploitation in 30 days

11thpercentile

Low risk: more likely to be exploited than 11% of all known CVEs.

References

Patch2

Vendor Advisory1

github.com

Product2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-03-18.