{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2023-26485",
        "ASSIGNER": "security-advisories@github.com",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "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. ### Impact A polynomial time complexity issue in cmark-gfm may lead to unbounded resource exhaustion and subsequent denial of service. ### Proof of concept ``` $ ~/cmark-gfm$ python3 -c 'pad = \"_\" * 100000; print(pad + \".\" + pad, end=\"\")' | time ./build/src/cmark-gfm --to plaintext ``` Increasing the number 10000 in the above commands causes the running time to increase quadratically. ### Patches This vulnerability have been patched in 0.29.0.gfm.10. ### Note on cmark and cmark-gfm XXX: TBD [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`. ### Credit We would like to thank @gravypod for reporting this vulnerability. ### References https://en.wikipedia.org/wiki/Time_complexity ### For more information If you have any questions or comments about this advisory: * Open an issue in [github/cmark-gfm](https://github.com/github/cmark-gfm)"
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "CWE-400: Uncontrolled Resource Consumption",
                        "cweId": "CWE-400"
                    }
                ]
            },
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "CWE-407: Inefficient Algorithmic Complexity",
                        "cweId": "CWE-407"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "github",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "cmark-gfm",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "=",
                                            "version_value": "< 0.29.0.gfm.10"
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://github.com/github/cmark-gfm/security/advisories/GHSA-r8vr-c48j-fcc5",
                "refsource": "MISC",
                "name": "https://github.com/github/cmark-gfm/security/advisories/GHSA-r8vr-c48j-fcc5"
            },
            {
                "url": "https://github.com/github/cmark-gfm/commit/07a66c9bc341f902878e37d7da8647d6ef150987",
                "refsource": "MISC",
                "name": "https://github.com/github/cmark-gfm/commit/07a66c9bc341f902878e37d7da8647d6ef150987"
            }
        ]
    },
    "source": {
        "advisory": "GHSA-r8vr-c48j-fcc5",
        "discovery": "UNKNOWN"
    },
    "impact": {
        "cvss": [
            {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "LOW",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                "version": "3.1"
            }
        ]
    }
}