{"answers":{"affected":"3 open source packages ship an affected version, including github.com/esm-dev/esm.sh. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27730 exists.","fix":"Upgrade github.com/esm-dev/esm.sh to 0.0.0-20250616164159-0593516c4cfa or later.","what":"CVE-2026-27730 is a high-severity server-side request forgery vulnerability in esm-dev esm.sh, published on 25 Feb 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-2026-27730 and fix it if it is affected.\n\nWhat it is: CVE-2026-27730 is a high-severity server-side request forgery vulnerability in esm-dev esm.sh, published on 25 Feb 2026. 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-2026-27730 exists.\n\nAffected packages and fixed versions:\n- github.com/esm-dev/esm.sh (Go): affected all versions; fixed in 0.0.0-20250616164159-0593516c4cfa\n- github.com/esm-dev/esm.sh (Go): affected all versions; fixed in 0.0.0-20250616164159-0593516c4cfa\n- github.com/esm-dev/esm.sh (Go): affected all versions; fixed in 0.0.0-20250616164159-0593516c4cfa\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-2026-27730/ (Markdown: https://insights.sbomify.com/CVE-2026-27730/index.md)","id":"CVE-2026-27730","markdown":"https://insights.sbomify.com/CVE-2026-27730/index.md","name":"CVE-2026-27730","record":{"aliases":["GHSA-p2v6-84h2-5x4r","GO-2026-4554"],"analysis":{"component_type":"cloud_service","fix_type":"no_fix_stated","impacts":["data_read","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"esm.sh CDN","requires_auth":"none","summary":"Attackers can bypass hostname validation to force the esm.sh CDN to fetch internal localhost services, exposing private network resources.","user_interaction":"not_required","vuln_class":"ssrf"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"esm.sh","vendor":"esm"}],"cvss":{"score":8.6,"severity":"high","source":"cna","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","version":"3.0"},"cwes":[{"id":"CWE-918","name":"Server-Side Request Forgery"}],"description":"esm.sh is a no-build content delivery network (CDN) for web development. Versions up to and including 137 have an SSRF vulnerability (CWE-918) in esm.sh’s `/http(s)` fetch route. The service tries to block localhost/internal targets, but the validation is based on hostname string checks and can be bypassed using DNS alias domains. This allows an external requester to make the esm.sh server fetch internal localhost services. As of time of publication, no known patched versions exist.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"esm.sh has SSRF localhost/private-network bypass in `/http(s)` module route","id":"CVE-2026-27730","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"ssrf","year":"2026"},"n_packages":3,"n_references":1,"next":{"headline":"AVideo has Authenticated Server-Side Request Forgery via downloadURL in aVideoEncoder.json.php","id":"CVE-2026-27732"},"packages":[{"ecosystem":"Go","fixed":["0.0.0-20250616164159-0593516c4cfa"],"introduced":["0"],"last_affected":[],"package":"github.com/esm-dev/esm.sh","purl":null,"source":"GHSA-p2v6-84h2-5x4r"},{"ecosystem":"Go","fixed":["0.0.0-20250616164159-0593516c4cfa"],"introduced":["0"],"last_affected":[],"package":"github.com/esm-dev/esm.sh","purl":"pkg:golang/github.com/esm-dev/esm.sh","source":"GHSA-p2v6-84h2-5x4r"},{"ecosystem":"Go","fixed":["0.0.0-20250616164159-0593516c4cfa"],"introduced":["0"],"last_affected":[],"package":"github.com/esm-dev/esm.sh","purl":"pkg:golang/github.com/esm-dev/esm.sh","source":"GO-2026-4554"}],"prev":{"headline":"Astro has memory exhaustion DoS due to missing request body size limit in Server Actions","id":"CVE-2026-27729"},"products":["esm.sh"],"published":"2026-02-25","related":[{"cvss_score":8.7,"headline":"esm.sh is vulnerable to full-response SSRF","id":"CVE-2025-50180","kev_date_added":null,"published":"2026-02-25"},{"cvss_score":8.2,"headline":"esm.sh CDN service has arbitrary file write via tarslip","id":"CVE-2025-65025","kev_date_added":null,"published":"2025-11-19"},{"cvss_score":7.7,"headline":"esm.sh has path traversal in `extractPackageTarball` that enables file writes from malicious packages","id":"CVE-2026-23644","kev_date_added":null,"published":"2026-01-18"},{"cvss_score":6.1,"headline":"esm.sh CDN service has JS Template Literal Injection in CSS-to-JavaScript","id":"CVE-2025-65026","kev_date_added":null,"published":"2025-11-19"}],"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":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-02-25","vendors":["esm-dev"]},"summary":"Attackers can bypass hostname validation to force the esm.sh CDN to fetch internal localhost services, exposing private network resources.","url":"https://insights.sbomify.com/CVE-2026-27730/"}