{"containers":{"cna":{"affected":[{"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["cow_spdy"],"packageName":"cowlib","packageURL":"pkg:hex/cowlib","product":"cowlib","programFiles":["src/cow_spdy.erl"],"programRoutines":[{"name":"cow_spdy:parse/2"},{"name":"cow_spdy:inflate/2"},{"name":"cow_spdy:parse_headers/2"},{"name":"cow_spdy:parse_headers/4"}],"repo":"https://github.com/ninenines/cowlib","vendor":"ninenines","versions":[{"lessThan":"2.16.1","status":"affected","version":"0.1.0","versionType":"semver"}]},{"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*"],"defaultStatus":"unaffected","modules":["cow_spdy"],"packageName":"ninenines/cowlib","packageURL":"pkg:github/ninenines/cowlib","product":"cowlib","programFiles":["src/cow_spdy.erl"],"programRoutines":[{"name":"cow_spdy:parse/2"},{"name":"cow_spdy:inflate/2"},{"name":"cow_spdy:parse_headers/2"},{"name":"cow_spdy:parse_headers/4"}],"repo":"https://github.com/ninenines/cowlib","vendor":"ninenines","versions":[{"lessThan":"16aad3fb9f81f5cda4d1706ff0c54237c619c282","status":"affected","version":"fad5c0049df278cc498b6cdb519b09e845a070a8","versionType":"git"}]}],"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>The application must use <tt>cow_spdy:parse/2</tt> to parse SPDY frames from an untrusted peer. cowboy itself does not use <tt>cow_spdy</tt>; only direct callers of the <tt>cow_spdy</tt> API are affected.</p>"}],"value":"The application must use cow_spdy:parse/2 to parse SPDY frames from an untrusted peer. cowboy itself does not use cow_spdy; only direct callers of the cow_spdy API are affected."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*","versionEndExcluding":"2.16.1","versionStartIncluding":"0.1.0","vulnerable":true}],"negate":false,"operator":"OR"}]}],"credits":[{"lang":"en","type":"finder","value":"Peter Ullrich"},{"lang":"en","type":"remediation developer","value":"Loïc Hoguin"}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows unauthenticated remote denial of service via memory exhaustion.</p><p><tt>cow_spdy:inflate/2</tt> in cowlib passes peer-supplied compressed bytes directly to <tt>zlib:inflate/2</tt> with no output size bound. The SPDY header compression dictionary (<tt>?ZDICT</tt>) 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 <tt>syn_stream</tt>, <tt>syn_reply</tt>, and <tt>headers</tt> frame types are all affected via <tt>cow_spdy:parse_headers/2</tt>.</p><p>This issue affects cowlib from 0.1.0 before 2.16.1.</p>"}],"value":"Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in ninenines cowlib allows unauthenticated remote denial of service via memory exhaustion.\n\ncow_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.\n\nThis issue affects cowlib from 0.1.0 before 2.16.1."}],"impacts":[{"capecId":"CAPEC-130","descriptions":[{"lang":"en","value":"CAPEC-130 Excessive Allocation"}]}],"metrics":[{"cvssV4_0":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.2,"baseSeverity":"HIGH","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-409","description":"CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-05-13T18:43:11.640Z","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","shortName":"EEF"},"references":[{"tags":["related","third-party-advisory"],"url":"https://cna.erlef.org/cves/CVE-2026-43970.html"},{"tags":["related"],"url":"https://osv.dev/vulnerability/EEF-CVE-2026-43970"},{"tags":["patch"],"url":"https://github.com/ninenines/cowlib/commit/16aad3fb9f81f5cda4d1706ff0c54237c619c282"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>Upgrade to cowlib 2.16.1 or later, in which the <tt>cow_spdy</tt> module has been removed entirely. No patched version of <tt>cow_spdy</tt> will be provided. Migrate away from SPDY, which has been deprecated since 2015 in favour of HTTP/2.</p>"}],"value":"Upgrade to cowlib 2.16.1 or later, in which the cow_spdy module has been removed entirely. No patched version of cow_spdy will be provided. Migrate away from SPDY, which has been deprecated since 2015 in favour of HTTP/2."}],"source":{"discovery":"EXTERNAL"},"title":"Decompression Bomb in cow_spdy:inflate/2 Allows Memory Exhaustion via Crafted SPDY Frame","x_generator":{"engine":"cvelib 1.8.0"}}},"cveMetadata":{"assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","assignerShortName":"EEF","cveId":"CVE-2026-43970","datePublished":"2026-05-13T18:43:11.640Z","dateReserved":"2026-05-04T18:23:25.574Z","dateUpdated":"2026-05-13T18:43:11.640Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"}