{"answers":{"affected":"3 open source packages ship an affected version, including github.com/sigstore/fulcio. It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-66506 in the wild and no public exploit code.","fix":"Upgrade github.com/sigstore/fulcio to 1.8.3 or later.","what":"CVE-2025-66506 is a high-severity denial of service vulnerability in sigstore fulcio, published on 4 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-66506 and fix it if it is affected.\n\nWhat it is: CVE-2025-66506 is a high-severity denial of service vulnerability in sigstore fulcio, published on 4 Dec 2025. 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-2025-66506 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- github.com/sigstore/fulcio (Go): affected all versions; fixed in 1.8.3\n- github.com/sigstore/fulcio (Go): affected all versions; fixed in 1.8.3\n- github.com/sigstore/fulcio (Go): affected all versions; fixed in 1.8.3\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-2025-66506/ (Markdown: https://insights.sbomify.com/CVE-2025-66506/index.md)","id":"CVE-2025-66506","markdown":"https://insights.sbomify.com/CVE-2025-66506/index.md","name":"CVE-2025-66506","record":{"aliases":["CLEANSTART-2026-KK01897","CLEANSTART-2026-TG34900","DEBIAN-CVE-2025-66506","GHSA-f83f-xpx7-ffpw","GO-2025-4193","MINI-22r3-82g9-3qq6","MINI-4mw6-5g7w-vwhq","MINI-56pw-3j58-r3f7","MINI-5xp8-9wjx-xh4r","MINI-6m5x-8p33-644h","MINI-6q37-vch2-7532","MINI-78vw-w53q-mwv7","MINI-7fvm-hrjm-7p3x","MINI-95vh-j973-2gw5","MINI-cfw4-843h-w9v3","MINI-cq6f-r5hh-798r","MINI-f24h-4wj4-9g33","MINI-ghm2-8x27-8vjx","MINI-ghr6-fhj7-w4h7","MINI-ghrm-pmxm-88v6","MINI-gv6g-fvm8-q8cf","MINI-hxf6-4ph4-gpxx","MINI-j6j4-v9gx-qw6h","MINI-mhrj-68j6-8jwc","MINI-mvf2-r6ph-674f","MINI-pmw6-jv27-qjmq","MINI-q7x7-9p8j-5g6m","MINI-vr2m-fcmr-jh6r","MINI-wv6c-h2gj-87p2","MINI-x644-hq54-q5r4","MINI-x9xv-fc8w-x4q5","MINI-xpf7-h8f2-2mg2","UBUNTU-CVE-2025-66506"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Fulcio certificate authority","requires_auth":"none","summary":"Attackers can cause excessive memory allocation and denial of service in Fulcio by sending OIDC tokens with many period characters.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"fulcio","vendor":"linuxfoundation"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-405","name":"Asymmetric Resource Consumption (Amplification)"}],"description":"Fulcio is a free-to-use certificate authority for issuing code signing certificates for an OpenID Connect (OIDC) identity. Prior to 1.8.3, function identity.extractIssuerURL splits (via a call to strings.Split) its argument (which is untrusted data) on periods. As a result, in the face of a malicious request with an (invalid) OIDC identity token in the payload containing many period characters, a call to extractIssuerURL incurs allocations to the tune of O(n) bytes (where n stands for the length of the function's argument), with a constant factor of about 16. This vulnerability is fixed in 1.8.3.","ecosystems":["Go"],"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":"Fulcio allocates excessive memory during token parsing","id":"CVE-2025-66506","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"denial_of_service","year":"2025"},"n_packages":3,"n_references":2,"next":{"headline":"1Panel – CAPTCHA Bypass via Client-Controlled Flag","id":"CVE-2025-66507"},"packages":[{"ecosystem":"Go","fixed":["1.8.3"],"introduced":["0"],"last_affected":[],"package":"github.com/sigstore/fulcio","purl":null,"source":"GHSA-f83f-xpx7-ffpw"},{"ecosystem":"Go","fixed":["1.8.3"],"introduced":["0"],"last_affected":[],"package":"github.com/sigstore/fulcio","purl":"pkg:golang/github.com/sigstore/fulcio","source":"GHSA-f83f-xpx7-ffpw"},{"ecosystem":"Go","fixed":["1.8.3"],"introduced":["0"],"last_affected":[],"package":"github.com/sigstore/fulcio","purl":"pkg:golang/github.com/sigstore/fulcio","source":"GO-2025-4193"}],"prev":{"headline":"Information disclosure in Affinity","id":"CVE-2025-66503"},"products":["fulcio"],"published":"2025-12-04","related":[{"cvss_score":5.8,"headline":"Fulcio vulnerable to Server-Side Request Forgery (SSRF) via MetaIssuer Regex Bypass","id":"CVE-2026-22772","kev_date_added":null,"published":"2026-01-12"}],"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":"Go Vulnerability Database","prefix":"GO"},{"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":"2025-12-05","vendors":["sigstore"]},"summary":"Attackers can cause excessive memory allocation and denial of service in Fulcio by sending OIDC tokens with many period characters.","url":"https://insights.sbomify.com/CVE-2025-66506/"}