CVE-2026-43970

EPSS 0.18%

cowlib: Decompression Bomb in cow_spdy:inflate/2 Allows Memory Exhaustion via Crafted SPDY Frame

Published: 5/13/2026Modified: 5/19/2026
Also known as:GHSA-84f2-rp86-235pEEF-CVE-2026-43970

Description

Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows unauthenticated remote denial of service via memory exhaustion. cow_spdy:inflate/2 in cowlib passes peer-supplied compressed bytes directly to zlib:inflate/2 with no output size bound. The SPDY header compression dictionary (?ZDICT) is public, and zlib compresses long runs of repeated bytes at roughly 1024:1, so a few kilobytes of SPDY frame payload can decompress to gigabytes on the BEAM heap, OOM-killing the node. A single unauthenticated SPDY frame is sufficient to trigger the condition. The parsers for syn_stream, syn_reply, and headers frame types are all affected via cow_spdy:parse_headers/2. This issue affects cowlib from 0.1.0 before 2.16.1.

Affected packages (2)

CVSS scores

SourceVersionSeverityVector
osvCVSS 4.0—CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References (6)