{"answers":{"affected":"3 open source packages ship an affected version, including github.com/caddyserver/caddy/v2. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27590 exists.","fix":"Upgrade github.com/caddyserver/caddy/v2 to 2.11.1 or later.","what":"CVE-2026-27590 is a high-severity path traversal vulnerability in caddyserver caddy, published on 24 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-2026-27590 and fix it if it is affected.\n\nWhat it is: CVE-2026-27590 is a high-severity path traversal vulnerability in caddyserver caddy, published on 24 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-2026-27590 exists.\n\nAffected packages and fixed versions:\n- github.com/caddyserver/caddy/v2 (Go): affected all versions; fixed in 2.11.1\n- github.com/caddyserver/caddy/v2 (Go): affected all versions; fixed in 2.11.1\n- github.com/caddyserver/caddy/v2 (Go): affected all versions; fixed in 2.11.1\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-2026-27590/ (Markdown: https://insights.sbomify.com/CVE-2026-27590/index.md)","id":"CVE-2026-27590","markdown":"https://insights.sbomify.com/CVE-2026-27590/index.md","name":"CVE-2026-27590","record":{"aliases":["DEBIAN-CVE-2026-27590","GHSA-5r3v-vc8m-m96g","GO-2026-4536","MINI-qmpr-6fhp-vvmr","UBUNTU-CVE-2026-27590"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["code_execution","security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"Caddy web server","requires_auth":"none","summary":"Caddy's FastCGI path splitting flaw allows attackers to execute unintended PHP files via Unicode case-folding confusion, potentially leading to remote code execution.","user_interaction":"not_required","vuln_class":"path_traversal"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"caddy","vendor":"caddyserver"}],"cvss":{"score":8.9,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P","version":"4.0"},"cwes":[{"id":"CWE-20","name":"Improper Input Validation"},{"id":"CWE-180","name":"Incorrect Behavior Order: Validate Before Canonicalize"}],"description":"Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's FastCGI path splitting logic computes the split index on a lowercased copy of the request path and then uses that byte index to slice the original path. This is unsafe for Unicode because `strings.ToLower()` can change UTF-8 byte length for some characters. As a result, Caddy can derive an incorrect `SCRIPT_NAME`/`SCRIPT_FILENAME` and `PATH_INFO`, potentially causing a request that contains `.php` to execute a different on-disk file than intended (path confusion). In setups where an attacker can control file contents (e.g., upload features), this can lead to unintended PHP execution of non-.php files (potential RCE depending on deployment). Version 2.11.1 fixes the issue.","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":"Caddy: Unicode case-folding length expansion causes incorrect split_path index in FastCGI transport","id":"CVE-2026-27590","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":null,"products":[],"type":"path_traversal","year":"2026"},"n_packages":3,"n_references":3,"next":{"headline":"Winter: Privilege escalation by authenticated backend users","id":"CVE-2026-27591"},"packages":[{"ecosystem":"Go","fixed":["2.11.1"],"introduced":["0"],"last_affected":[],"package":"github.com/caddyserver/caddy/v2","purl":null,"source":"GHSA-5r3v-vc8m-m96g"},{"ecosystem":"Go","fixed":["2.11.1"],"introduced":["0"],"last_affected":[],"package":"github.com/caddyserver/caddy/v2","purl":"pkg:golang/github.com/caddyserver/caddy/v2","source":"GHSA-5r3v-vc8m-m96g"},{"ecosystem":"Go","fixed":["2.11.1"],"introduced":["0"],"last_affected":[],"package":"github.com/caddyserver/caddy/v2","purl":"pkg:golang/github.com/caddyserver/caddy/v2","source":"GO-2026-4536"}],"prev":{"headline":"Caddy vulnerable to cross-origin config application via local admin API /load (caddy)","id":"CVE-2026-27589"},"products":["caddy"],"published":"2026-02-24","related":[{"cvss_score":9.8,"headline":"Caddy vulnerable to Authentication Bypass due to mishandling of TLS client authentication","id":"CVE-2018-21246","kev_date_added":null,"published":"2020-06-15"},{"cvss_score":8.8,"headline":"Caddy's mTLS client authentication silently fails open when CA certificate file is missing or malformed","id":"CVE-2026-27586","kev_date_added":null,"published":"2026-02-24"},{"cvss_score":8.1,"headline":"Caddy: Unsafe Unicode Handling in FastCGI splitPos Allows Execution of Non-PHP Files","id":"CVE-2026-45135","kev_date_added":null,"published":"2026-06-23"},{"cvss_score":8.1,"headline":"Caddy: FastCGI header normalization bypass in `forward_auth copy_headers`","id":"CVE-2026-52845","kev_date_added":null,"published":"2026-06-23"},{"cvss_score":8.1,"headline":"Caddy forward_auth copy_headers Does Not Strip Client-Supplied Headers, Allowing Identity Injection and Privilege Escalation","id":"CVE-2026-30851","kev_date_added":null,"published":"2026-03-07"},{"cvss_score":7.7,"headline":"Caddy: MatchPath %xx (escaped-path) branch skips case normalization, enabling path-based route/auth bypass","id":"CVE-2026-27587","kev_date_added":null,"published":"2026-02-24"}],"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":"poc","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-02-27","vendors":["caddyserver"]},"summary":"Caddy's FastCGI path splitting flaw allows attackers to execute unintended PHP files via Unicode case-folding confusion, potentially leading to remote code execution.","url":"https://insights.sbomify.com/CVE-2026-27590/"}