{"answers":{"affected":"3 open source packages ship an affected version, including github.com/axllent/mailpit. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-21859 exists.","fix":"Upgrade github.com/axllent/mailpit to 1.28.1 or later.","what":"CVE-2026-21859 is a medium-severity server-side request forgery vulnerability in axllent mailpit, published on 7 Jan 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-2026-21859 and fix it if it is affected.\n\nWhat it is: CVE-2026-21859 is a medium-severity server-side request forgery vulnerability in axllent mailpit, published on 7 Jan 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-2026-21859 exists.\n\nAffected packages and fixed versions:\n- github.com/axllent/mailpit (Go): affected all versions; fixed in 1.28.1\n- github.com/axllent/mailpit (Go): affected all versions; fixed in 1.28.1\n- github.com/axllent/mailpit (Go): affected all versions; fixed in 1.28.1\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-2026-21859/ (Markdown: https://insights.sbomify.com/CVE-2026-21859/index.md)","id":"CVE-2026-21859","markdown":"https://insights.sbomify.com/CVE-2026-21859/index.md","name":"CVE-2026-21859","record":{"aliases":["GHSA-8v65-47jx-7mfr","GO-2026-4284"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["data_read","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Email testing tool","requires_auth":"none","summary":"Attackers can exploit the /proxy endpoint to access internal network resources via Server-Side Request Forgery in Mailpit.","user_interaction":"not_required","vuln_class":"ssrf"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"mailpit","vendor":"axllent"}],"cvss":{"score":5.8,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-918","name":"Server-Side Request Forgery"}],"description":"Mailpit is an email testing tool and API for developers. Versions 1.28.0 and below have a Server-Side Request Forgery (SSRF) vulnerability in the /proxy endpoint, allowing attackers to make requests to internal network resources. The /proxy endpoint validates http:// and https:// schemes, but it does not block internal IP addresses, enabling attackers to access internal services and APIs. This vulnerability is limited to HTTP GET requests with minimal headers. The issue is fixed in version 1.28.1.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":1,"refs":[{"date":null,"kind":"nuclei","ref":"http/cves/2026/CVE-2026-21859.yaml","stars":null,"title":"Mailpit \u003c 1.28.3 - Server-Side Request Forgery"}],"tier":"weaponised"},"has_fix":true,"headline":"Mailpit Proxy Endpoint is Vulnerable to Server-Side Request Forgery (SSRF)","id":"CVE-2026-21859","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"ssrf","year":"2026"},"n_packages":3,"n_references":2,"next":{"headline":"Werkzeug safe_join() allows Windows special device names with compound extensions","id":"CVE-2026-21860"},"packages":[{"ecosystem":"Go","fixed":["1.28.1"],"introduced":["0"],"last_affected":[],"package":"github.com/axllent/mailpit","purl":null,"source":"GHSA-8v65-47jx-7mfr"},{"ecosystem":"Go","fixed":["1.28.1"],"introduced":["0"],"last_affected":[],"package":"github.com/axllent/mailpit","purl":"pkg:golang/github.com/axllent/mailpit","source":"GHSA-8v65-47jx-7mfr"},{"ecosystem":"Go","fixed":["1.28.1"],"introduced":["0"],"last_affected":[],"package":"github.com/axllent/mailpit","purl":"pkg:golang/github.com/axllent/mailpit","source":"GO-2026-4284"}],"prev":{"headline":"n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling","id":"CVE-2026-21858"},"products":["mailpit"],"published":"2026-01-07","related":[{"cvss_score":7.5,"headline":"Mailpit: Unauthenticated remote memory-exhaustion DoS via unlimited SMTP DATA and /api/v1/send body sizes","id":"CVE-2026-45713","kev_date_added":null,"published":"2026-07-20"},{"cvss_score":6.5,"headline":"Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails","id":"CVE-2026-22689","kev_date_added":null,"published":"2026-01-10"},{"cvss_score":5.9,"headline":"Mailpit: Path traversal \u0026 arbitrary file write in mailpit dump --http via attacker-controlled message IDs","id":"CVE-2026-45711","kev_date_added":null,"published":"2026-07-20"},{"cvss_score":5.9,"headline":"Mailpit: Concurrent map read \u0026 write in proxy CSS rewriter - remote unauth crash (fatal error: concurrent map read and map write)","id":"CVE-2026-45712","kev_date_added":null,"published":"2026-07-20"},{"cvss_score":5.8,"headline":"Mailpit has an incomplete fix for GHSA-6jxm: HTML check still permits SSRF to private/loopback/IMDS via missing IP-filter dialer","id":"CVE-2026-45709","kev_date_added":null,"published":"2026-07-20"},{"cvss_score":5.8,"headline":"Mailpit is Vulnerable to Server-Side Request Forgery (SSRF) via Link Check API","id":"CVE-2026-27808","kev_date_added":null,"published":"2026-02-25"},{"cvss_score":5.8,"headline":"Mailpit Vulnerable to Server-Side Request Forgery (SSRF) via HTML Check API","id":"CVE-2026-23845","kev_date_added":null,"published":"2026-01-19"}],"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)"},{"class":"attribution","licence":"MIT","name":"Nuclei templates"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-01-08","vendors":["axllent"]},"summary":"Attackers can exploit the /proxy endpoint to access internal network resources via Server-Side Request Forgery in Mailpit.","url":"https://insights.sbomify.com/CVE-2026-21859/"}