{"id":"UBUNTU-CVE-2026-7790","details":"Uncontrolled Resource Consumption vulnerability in ninenines cowlib (cow_http_te module) allows Excessive Allocation. The chunked transfer-encoding parser in cow_http_te accepts an unbounded number of hex digits in the chunk-size field. Each digit causes a bignum multiplication (Len * 16 + digit), so parsing N hex digits requires O(N²) CPU work and O(N) memory. Additionally, when input is drip-fed, the parser discards the accumulated length on each partial read and restarts from zero on resumption, raising the cost to O(N³). An unauthenticated remote attacker can exploit this by sending an HTTP/1.1 request with Transfer-Encoding: chunked and a very long chunk-size hex string to cause denial of service through CPU exhaustion and memory amplification. This vulnerability is associated with program file src/cow_http_te.erl and program routines cow_http_te:stream_chunked/2, cow_http_te:chunked_len/4. This issue affects cowlib: from 0.6.0 before 2.16.1.","modified":"2026-06-24T11:00:25.196515392Z","published":"2026-05-11T19:16:00Z","upstream":["CVE-2026-7790"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-7790"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-7790"},{"type":"REPORT","url":"https://cna.erlef.org/cves/CVE-2026-7790.html"},{"type":"REPORT","url":"https://osv.dev/vulnerability/EEF-CVE-2026-7790"},{"type":"REPORT","url":"https://github.com/ninenines/cowlib/commit/a4b8039ce8c93ab00867ef6b7e888822c09f4369"}],"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-2026-7790.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-2026-7790.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-2026-7790.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_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-2026-7790.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_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-2026-7790.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_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-2026-7790.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-2026-7790.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}