{"answers":{"affected":"2 open source packages ship an affected version, including league/commonmark. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-86429 in the wild and no public exploit code.","fix":"Upgrade league/commonmark to 2.9.1 or later.","what":"CVE-2026-86429 is a high-severity denial of service vulnerability in thephpleague commonmark, published on 7 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-86429 and fix it if it is affected.\n\nWhat it is: CVE-2026-86429 is a high-severity denial of service vulnerability in thephpleague commonmark, published on 7 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-86429 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- league/commonmark (Packagist): affected from 1.5.0; fixed in 2.9.1\n- league/commonmark (Packagist): affected from 1.5.0; fixed in 2.9.1\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-2026-86429/ (Markdown: https://insights.sbomify.com/CVE-2026-86429/index.md)","id":"CVE-2026-86429","markdown":"https://insights.sbomify.com/CVE-2026-86429/index.md","name":"CVE-2026-86429","record":{"aliases":["DEBIAN-CVE-2026-86429","GHSA-7x8h-jg2x-pjm5","GHSA-jjv6-8j6v-6j52","UBUNTU-CVE-2026-86429"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"PHP Markdown library","requires_auth":"none","summary":"An attacker can cause denial of service via CPU exhaustion in the commonmark library if specific optional extensions are enabled.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[{"product":"commonmark","vendor":"thephpleague"}],"cvss":{"score":8.7,"severity":"high","source":"cna","vector":"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","version":"4.0"},"cwes":[{"id":"CWE-407","name":"Inefficient Algorithmic Complexity"}],"description":"The league/commonmark (thephpleague/commonmark) library in versions \u003e= 1.5.0 and \u003c 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.","ecosystems":["Packagist"],"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":"commonmark before 2.9.1 Denial of Service via SmartPunct and Attributes","id":"CVE-2026-86429","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Packagist","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":2,"n_references":2,"next":{"headline":"league/commonmark before 2.9.1 Denial of Service via parsing","id":"CVE-2026-86430"},"packages":[{"ecosystem":"Packagist","fixed":["2.9.1"],"introduced":["1.5.0"],"last_affected":[],"package":"league/commonmark","purl":null,"source":"GHSA-jjv6-8j6v-6j52"},{"ecosystem":"Packagist","fixed":["2.9.1"],"introduced":["1.5.0"],"last_affected":[],"package":"league/commonmark","purl":"pkg:composer/league/commonmark","source":"GHSA-jjv6-8j6v-6j52"}],"prev":{"headline":"commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes","id":"CVE-2026-86428"},"products":["commonmark"],"published":"2026-09-07","related":[{"cvss_score":8.7,"headline":"commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes","id":"CVE-2026-86428","kev_date_added":null,"published":"2026-09-07"},{"cvss_score":8.7,"headline":"league/commonmark before 2.9.1 Denial of Service via parsing","id":"CVE-2026-86430","kev_date_added":null,"published":"2026-09-07"},{"cvss_score":6.9,"headline":"commonmark before 2.9.1 XSS via AttributesExtension form feed bypass","id":"CVE-2026-86431","kev_date_added":null,"published":"2026-09-07"},{"cvss_score":6.3,"headline":"league/commonmark has an embed extension allowed_domains bypass","id":"CVE-2026-33347","kev_date_added":null,"published":"2026-03-24"},{"cvss_score":6.1,"headline":"Moderate severity vulnerability that affects league/commonmark","id":"CVE-2019-10010","kev_date_added":null,"published":"2019-03-24"},{"cvss_score":6.1,"headline":"PHP League CommonMark vulnerable to Cross-Site Scripting (XSS)","id":"CVE-2018-20583","kev_date_added":null,"published":"2018-12-30"}],"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":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-08","vendors":["thephpleague"]},"summary":"An attacker can cause denial of service via CPU exhaustion in the commonmark library if specific optional extensions are enabled.","url":"https://insights.sbomify.com/CVE-2026-86429/"}