{"answers":{"affected":"It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-26485 exists.","fix":"Upgrade to a fixed version.","what":"CVE-2023-26485 is a medium-severity denial of service vulnerability in github cmark-gfm, published on 31 Mar 2023. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2023-26485 and fix it if it is affected.\n\nWhat it is: CVE-2023-26485 is a medium-severity denial of service vulnerability in github cmark-gfm, published on 31 Mar 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-26485 exists.\n\nAffected product: github cmark-gfm. No package-level version data is available, so check the vendor advisory linked from the reference page.\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-2023-26485/ (Markdown: https://insights.sbomify.com/CVE-2023-26485/index.md)","id":"CVE-2023-26485","markdown":"https://insights.sbomify.com/CVE-2023-26485/index.md","name":"CVE-2023-26485","record":{"aliases":["DEBIAN-CVE-2023-26485","GHSA-r8vr-c48j-fcc5","UBUNTU-CVE-2023-26485"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Markdown parsing library","requires_auth":"none","summary":"Attackers can cause denial of service in cmark-gfm by submitting input with many underscores, triggering quadratic time complexity and resource exhaustion.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"cmark-gfm","vendor":"github"}],"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-407","name":"Inefficient Algorithmic Complexity"},{"id":"CWE-400","name":"Uncontrolled Resource Consumption"}],"description":"cmark-gfm is GitHub's fork of cmark, a CommonMark parsing and rendering library and program in C. A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. This CVE covers quadratic complexity issues when parsing text which leads with either large numbers of `_` characters. This issue has been addressed in version 0.29.0.gfm.10. Users are advised to upgrade. Users unable to upgrade should validate that their input comes from trusted sources.\n\n### Impact\n\nA polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service.\n\n### Proof of concept\n\n```\n$ ~/cmark-gfm$ python3 -c 'pad = \"_\" * 100000; print(pad + \".\" + pad, end=\"\")' | time ./build/src/cmark-gfm --to plaintext\n```\n\nIncreasing the number 10000 in the above commands causes the running time to increase quadratically.\n\n### Patches\n\nThis vulnerability have been patched in 0.29.0.gfm.10.\n\n### Note on cmark and cmark-gfm\n\nXXX: TBD\n\n[cmark-gfm](https://github.com/github/cmark-gfm) is a fork of [cmark](https://github.com/commonmark/cmark) that adds the GitHub Flavored Markdown extensions. The two codebases have diverged over time, but share a common core. These bugs affect both `cmark` and `cmark-gfm`. \n\n### Credit\n\nWe would like to thank @gravypod for reporting this vulnerability.\n\n### References\n\nhttps://en.wikipedia.org/wiki/Time_complexity\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n* Open an issue in [github/cmark-gfm](https://github.com/github/cmark-gfm)","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Quadratic complexity may lead to a denial of service in cmark-gfm","id":"CVE-2023-26485","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"denial_of_service","year":"2023"},"n_packages":0,"n_references":2,"next":{"headline":"Vega `scale` expression function cross site scripting","id":"CVE-2023-26486"},"packages":[],"prev":{"headline":"On a compromised KubeVirt node, the virt-handler service account can be used to modify all node specs","id":"CVE-2023-26484"},"products":["cmark-gfm"],"published":"2023-03-31","related":[{"cvss_score":9.8,"headline":"CommonMarker Integer Overflow Vulnerability","id":"CVE-2024-22051","kev_date_added":null,"published":"2024-01-04"},{"cvss_score":6.4,"headline":"Quadratic complexity bugs may lead to a denial of service","id":"CVE-2023-37463","kev_date_added":null,"published":"2023-07-13"},{"cvss_score":5.3,"headline":"Quadratic complexity may lead to a denial of service in cmark-gfm","id":"CVE-2023-24824","kev_date_added":null,"published":"2023-03-31"},{"cvss_score":5.3,"headline":"cmark-gfm out-of-bounds read in validate_protocol","id":"CVE-2023-22485","kev_date_added":null,"published":"2023-01-24"},{"cvss_score":3.5,"headline":"cmark-gfm Quadratic complexity bug in handle_close_bracket may lead to a denial of service","id":"CVE-2023-22486","kev_date_added":null,"published":"2023-01-24"},{"cvss_score":3.5,"headline":"cmark-gfm Quadratic complexity bugs may lead to a denial of service","id":"CVE-2023-22483","kev_date_added":null,"published":"2023-01-23"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"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":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2025-02-11","vendors":["github"]},"summary":"Attackers can cause denial of service in cmark-gfm by submitting input with many underscores, triggering quadratic time complexity and resource exhaustion.","url":"https://insights.sbomify.com/CVE-2023-26485/"}