{"answers":{"affected":"2 open source packages ship an affected version, including mdex and mdex_native.","exploited":"There is no known exploitation of CVE-2026-53428 in the wild and no public exploit code.","fix":"Upgrade mdex to 0.12.3 or later.","what":"CVE-2026-53428 is a medium-severity denial of service vulnerability in leandrocp mdex, published on 29 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-53428 and fix it if it is affected.\n\nWhat it is: CVE-2026-53428 is a medium-severity denial of service vulnerability in leandrocp mdex, published on 29 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-53428 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- mdex (Hex): affected from 0.11.0; fixed in 0.12.3\n- mdex_native (Hex): affected from 0.1.0; fixed in 0.2.3\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-2026-53428/ (Markdown: https://insights.sbomify.com/CVE-2026-53428/index.md)","id":"CVE-2026-53428","markdown":"https://insights.sbomify.com/CVE-2026-53428/index.md","name":"CVE-2026-53428","record":{"aliases":["EEF-CVE-2026-53428","GHSA-j93q-9cvj-rxfm"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Elixir Markdown library","requires_auth":"none","summary":"An unauthenticated attacker can cause a denial of service by supplying Markdown with a large highlight_lines range, triggering excessive memory allocation.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"EEF","cpe":[],"cvss":{"score":6.9,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H","version":"4.0"},"cwes":[{"id":"CWE-789","name":"Memory Allocation with Excessive Size Value"}],"description":"Memory Allocation with Excessive Size Value vulnerability in leandrocp mdex allows an unauthenticated attacker to cause a denial of service through unbounded memory allocation.\n\ncomrak_nif::lumis_adapter::LumisAdapter::parse_highlight_lines in native/comrak_nif/src/lumis_adapter.rs eagerly expands a user-controlled inclusive line range from a fenced code block's highlight_lines decorator into a Vec\u003cusize\u003e, pushing one element per integer in the range with no upper bound on the range size. An attacker who can supply Markdown that an application renders with MDEx.to_html/2 (for example a comment, chat message, or wiki page) can embed a code block whose info string is rust highlight_lines=\"1-100000000\", forcing the native adapter to allocate roughly 8 bytes per line in the range.\n\nA payload that differs by only a few bytes can therefore allocate hundreds of megabytes, and a sufficiently large range (for example 1-2000000000) exhausts host memory and aborts the BEAM, denying service to every user of the rendering process. The per-line write loop additionally tests membership with a linear scan over the same vector, degrading rendering to a quadratic cost even for ranges that do not immediately exhaust memory.\n\nThe vulnerable native code originally shipped inside mdex (in native/comrak_nif/src/lumis_adapter.rs) and was later extracted into the separate mdex_native package (native/mdex_native_nif/src/lumis_adapter.rs), where it remains unpatched.\n\nThis issue affects mdex from 0.11.0 before 0.12.3, and mdex_native from 0.1.0 before 0.2.3.","ecosystems":["Hex"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Unbounded memory allocation in highlight_lines range expansion in mdex","id":"CVE-2026-53428","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Hex","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":2,"n_references":4,"next":{"headline":"Unbounded native memory leak in mdex escaped-tag rendering enables unauthenticated denial of service","id":"CVE-2026-53429"},"packages":[{"ecosystem":"Hex","fixed":["0.12.3"],"introduced":["0.11.0"],"last_affected":[],"package":"mdex","purl":"pkg:hex/mdex","source":"EEF-CVE-2026-53428"},{"ecosystem":"Hex","fixed":["0.2.3"],"introduced":["0.1.0"],"last_affected":[],"package":"mdex_native","purl":"pkg:hex/mdex_native","source":"EEF-CVE-2026-53428"}],"prev":{"headline":"Cross-site scripting in MDEx via unescaped highlight_lines_class code-fence attribute","id":"CVE-2026-53427"},"products":["mdex","mdex_native"],"published":"2026-06-29","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"Erlang Ecosystem Foundation","prefix":"EEF"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-06-30","vendors":["leandrocp"]},"summary":"An unauthenticated attacker can cause a denial of service by supplying Markdown with a large highlight_lines range, triggering excessive memory allocation.","url":"https://insights.sbomify.com/CVE-2026-53428/"}