{"id":"UBUNTU-CVE-2026-43970","details":"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.","modified":"2026-05-20T22:03:06.282819667Z","published":"2026-05-13T19:17:00Z","upstream":["CVE-2026-43970"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-43970"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-43970"},{"type":"REPORT","url":"https://cna.erlef.org/cves/CVE-2026-43970.html"},{"type":"REPORT","url":"https://osv.dev/vulnerability/EEF-CVE-2026-43970"},{"type":"REPORT","url":"https://github.com/ninenines/cowlib/commit/16aad3fb9f81f5cda4d1706ff0c54237c619c282"},{"type":"REPORT","url":"https://github.com/ninenines/cowlib/commit/16aad3fb9f81f5cda4d1706ff0c54237c619c282"}],"affected":[{"package":{"name":"erlang-cowlib","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/erlang-cowlib?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.0-1","binary_name":"erlang-cowlib"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-43970.json"}},{"package":{"name":"erlang-cowlib","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/erlang-cowlib?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-2"],"ecosystem_specific":{"binaries":[{"binary_name":"erlang-cowlib","binary_version":"1.3.0-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-43970.json"}},{"package":{"name":"erlang-cowlib","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/erlang-cowlib?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.0-3","binary_name":"erlang-cowlib"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-43970.json"}},{"package":{"name":"erlang-cowlib","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/erlang-cowlib?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-3"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.0-3","binary_name":"erlang-cowlib"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-43970.json"}},{"package":{"name":"erlang-cowlib","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/erlang-cowlib?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-3"],"ecosystem_specific":{"binaries":[{"binary_name":"erlang-cowlib","binary_version":"1.3.0-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-43970.json"}},{"package":{"name":"erlang-cowlib","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/erlang-cowlib?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-3"],"ecosystem_specific":{"binaries":[{"binary_name":"erlang-cowlib","binary_version":"1.3.0-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-43970.json"}},{"package":{"name":"erlang-cowlib","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/erlang-cowlib?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.3.0-3","1.3.0-3build1"],"ecosystem_specific":{"binaries":[{"binary_name":"erlang-cowlib","binary_version":"1.3.0-3build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-43970.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"},{"type":"Ubuntu","score":"medium"}]}