CVE-2026-57487: libupnp chunked HTTP bodies can bypass g_maxContentLength and be fully buffered

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-10-16 · updated 2026-10-23
Weakness: CWE-770

Description

pupnp is an SDK for development of UPnP device and control point applications. Prior to 2.0.2, Transfer-Encoding: chunked causes the HTTP parser in upnp/src/genlib/net/http/httpparser.c to leave parser->content_length at zero while parser_parse_chunky_entity and parser_parse_chunky_body accumulate decoded bytes in parser->msg.entity. The g_maxContentLength checks in http_RecvMessage in upnp/src/genlib/net/http/httpreadwrite.c therefore reject oversized numeric Content-Length bodies but do not enforce the same limit on decoded chunked bodies. A remote peer that can reach a SOAP, GENA, miniserver, or control-point HTTP response path can make the process buffer an entity larger than the configured maximum, causing resource exhaustion and denial of service. This issue is fixed in 2.0.2.

Affected products

pupnp: before 2.0.2 — fixed in 2.0.2

How to fix

Upgrade to a fixed version: pupnp 2.0.2. Check the vendor advisory for mitigations.

References

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