{"answers":{"affected":"3 open source packages ship an affected version, including h2.","exploited":"There is no known exploitation of CVE-2026-71554 in the wild and no public exploit code.","fix":"Upgrade h2 to 4.4.1 or later.","what":"CVE-2026-71554 is a medium-severity vulnerability in python-hyper h2, published on 6 Aug 2026."},"fix_prompt":"Check this codebase for CVE-2026-71554 and fix it if it is affected.\n\nWhat it is: CVE-2026-71554 is a medium-severity vulnerability in python-hyper h2, published on 6 Aug 2026. \nExploitation: There is no known exploitation of CVE-2026-71554 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- h2 (PyPI): affected all versions; fixed in 4.4.1\n- h2 (PyPI): affected all versions; fixed in 4.4.1\n- h2 (PyPI): affected all versions; fixed in 4.4.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-71554/ (Markdown: https://insights.sbomify.com/CVE-2026-71554/index.md)","id":"CVE-2026-71554","markdown":"https://insights.sbomify.com/CVE-2026-71554/index.md","name":"CVE-2026-71554","record":{"aliases":["BELL-CVE-2026-71554","CLEANSTART-2026-VQ36233","DEBIAN-CVE-2026-71554","ECHO-0f77-53c4-f946","GHSA-6hr6-w5qg-qmwg","MGASA-2026-0409","MINI-2r53-gchr-m3j5","MINI-4x7q-q69h-mrqh","MINI-fr67-7x89-39fr","PYSEC-2026-3628","SUSE-SU-2026:23563-1","SUSE-SU-2026:3970-1","SUSE-SU-2026:3972-1","UBUNTU-CVE-2026-71554","openSUSE-SU-2026:11523-1","openSUSE-SU-2026:21693-1"],"analysis":null,"analysis_generated_by":null,"assigner":"GitHub_M","cpe":[],"cvss":{"score":5.3,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","version":"3.1"},"cwes":[{"id":"CWE-444","name":"Inconsistent Interpretation of HTTP Requests"}],"description":"h2 is a pure-Python implementation of a HTTP/2 protocol stack. Versions up to and including 4.4.0 accept request header blocks containing more than one Host header, and forward every Host header to the consuming application. Where the consumer downgrades HTTP/2 to HTTP/1.1, the resulting request carries two Host header lines, providing a request smuggling primitive. This issue is fixed in version 4.4.1.","ecosystems":["PyPI","SUSE:Linux Enterprise Module for Python 3 15 SP7","SUSE:Linux Enterprise Module for Server Applications 15 SP7","SUSE:Linux Enterprise Server 16.0","SUSE:Linux Enterprise Server for SAP applications 16.0","openSUSE:Leap 16.0","openSUSE:Tumbleweed"],"exploits":{"exploitdb":0,"first_seen":"2026-08-07","github_poc":1,"max_poc_stars":1,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-08-07T21:15:48Z","kind":"github_poc","ref":"https://github.com/SunandM/poc-h2-CVE-2026-71554","stars":1,"title":"PoC for CVE-2026-71554 - h2 duplicate Host header request smuggling primitive (fixed in 4.4.1)"}],"tier":"poc_unverified"},"has_fix":true,"headline":"h2: Duplicate Host header could facilitate request smuggling","id":"CVE-2026-71554","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":null,"year":"2026"},"n_packages":9,"n_references":2,"next":{"headline":"PILOS: Reverse tabnabbing in room description","id":"CVE-2026-71555"},"packages":[{"ecosystem":"PyPI","fixed":["4.4.1"],"introduced":["0"],"last_affected":[],"package":"h2","purl":null,"source":"GHSA-6hr6-w5qg-qmwg"},{"ecosystem":"PyPI","fixed":["4.4.1"],"introduced":["0"],"last_affected":[],"package":"h2","purl":"pkg:pypi/h2","source":"GHSA-6hr6-w5qg-qmwg"},{"ecosystem":"PyPI","fixed":["4.4.1"],"introduced":["0"],"last_affected":[],"package":"h2","purl":"pkg:pypi/h2","source":"PYSEC-2026-3628"},{"ecosystem":"SUSE:Linux Enterprise Module for Python 3 15 SP7","fixed":["4.1.0-150400.8.9.1"],"introduced":["0"],"last_affected":[],"package":"python-h2","purl":"pkg:rpm/suse/python-h2\u0026distro=SUSE%20Linux%20Enterprise%20Module%20for%20Python%203%2015%20SP7","source":"SUSE-SU-2026:3970-1"},{"ecosystem":"SUSE:Linux Enterprise Module for Server Applications 15 SP7","fixed":["3.2.0-150200.3.8.1"],"introduced":["0"],"last_affected":[],"package":"python-h2","purl":"pkg:rpm/suse/python-h2\u0026distro=SUSE%20Linux%20Enterprise%20Module%20for%20Server%20Applications%2015%20SP7","source":"SUSE-SU-2026:3972-1"},{"ecosystem":"SUSE:Linux Enterprise Server 16.0","fixed":["4.2.0-160000.4.1"],"introduced":["0"],"last_affected":[],"package":"python-h2","purl":"pkg:rpm/suse/python-h2\u0026distro=SUSE%20Linux%20Enterprise%20Server%2016.0","source":"SUSE-SU-2026:23563-1"},{"ecosystem":"SUSE:Linux Enterprise Server for SAP applications 16.0","fixed":["4.2.0-160000.4.1"],"introduced":["0"],"last_affected":[],"package":"python-h2","purl":"pkg:rpm/suse/python-h2\u0026distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20applications%2016.0","source":"SUSE-SU-2026:23563-1"},{"ecosystem":"openSUSE:Leap 16.0","fixed":["4.2.0-160000.4.1"],"introduced":["0"],"last_affected":[],"package":"python-h2","purl":"pkg:rpm/opensuse/python-h2\u0026distro=openSUSE%20Leap%2016.0","source":"openSUSE-SU-2026:21693-1"},{"ecosystem":"openSUSE:Tumbleweed","fixed":["4.4.1-1.1"],"introduced":["0"],"last_affected":[],"package":"python-h2","purl":"pkg:rpm/opensuse/python-h2\u0026distro=openSUSE%20Tumbleweed","source":"openSUSE-SU-2026:11523-1"}],"prev":{"headline":"ApostropheCMS: 2nd-order prototype pollution via PATCH leading to single-request persistent DoS","id":"CVE-2026-71553"},"products":["h2"],"published":"2026-08-06","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"SUSE"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"openSUSE"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-08","vendors":["python-hyper"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-71554/"}