iopress: Buffer over-read in chunked HTTP request parser
Summary
iopress is a native HTTP server library for Node.js. In versions before 1.0.5, the parser for chunked HTTP requests in @iopress/core reads beyond the end of the received data when a request declares a chunk size larger than the body actually sent. A remote, unauthenticated attacker can trigger this with a crafted request, which may crash the process (denial of service) and, depending on the heap layout, leak small amounts of adjacent memory. Only applications that use this package and are reachable over the network are exposed.
Affected
- @iopress/core versions below 1.0.5 according to the CVE record (CNA: GitHub).
- A third-party database lists the range as up to 1.0.4 and a different CWE. The CNA and vendor data are treated as authoritative.
Fixed in
- Upgrade to @iopress/core 1.0.5 or later.
Workaround
Unknown. The vendor documents no workaround.
Exploitation
- No evidence of active exploitation found.
- No public proof of concept found in the checked sources.
Our recommendation
- Check whether @iopress/core is used (for example, search package-lock.json or yarn.lock).
- Upgrade affected installations to 1.0.5 or later.
- If an internet-facing service uses iopress, prioritise the update and monitor for crashes or unusual requests.
- Priority: low for most SMEs, medium if an internet-facing iopress service is in use.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE Record CVE-2026-65833 www.cve.org
- GitHub Security Advisory GHSA-pvr5-58cf-rgv6 github.com
- iopress Release v1.0.5 github.com
- VulDB entry 435955 vuldb.com
- Strix CVE entry CVE-2026-65833 www.strix.ai
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 20:38.
Original description (NVD)
iopress is a native HTTP server for Node.js with platform-specific async I/O. Prior to version 1.0.5, the chunked-transfer-encoding HTTP request parser in @iopress/core reads past the end of the input buffer when a request declares a chunk size larger than the body actually received. This results in a heap-buffer-over-read. This issue has been patched in version 1.0.5.
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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