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.
CVE-2026-32239
This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.5
- EG Score
- 6.5(low)
- EG Risk
- 34(Track)EG Risk 34/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity65% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 11%
- KEV
- Not listed
Published
March 12, 2026
Last Modified
June 17, 2026
References (5)
- security-advisories@githubhttps://capnproto.org/capnproto-c++-1.4.0.tar.gz
- security-advisories@githubhttps://capnproto.org/capnproto-c++-win32-1.4.0.zip
- security-advisories@githubhttps://github.com/capnproto/capnproto/commit/2744b3c012b4aa3c31cefb61ec656829fa5c0e36
- security-advisories@githubhttps://github.com/capnproto/capnproto/commit/e929f0ba7901a6b8f4b5ba9a4db00af43288cbb0
- security-advisories@githubhttps://github.com/capnproto/capnproto/security/advisories/GHSA-qjx3-pp3m-9jpm
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 1× in last 7d / 1× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-27 13:39 UTCEG score recompute
Related CVEs(same CWE)
Same CWE
10 shownCWE-190
Frequently asked(5)
What is CVE-2026-32239?
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-32239
Is Your Infrastructure Affected by CVE-2026-32239?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.