# CVE-2026-72815: go-chi chi v5.2.1 IP Spoofing via X-Forwarded-For Header > Attackers can bypass IP-based access controls and rate limits by spoofing the X-Forwarded-For header in go-chi chi middleware. - **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 14 Aug 2026 - **Updated:** 8 Oct 2026 - **Also known as:** CLEANSTART-2026-CG94137, CLEANSTART-2026-SZ57384, CLEANSTART-2026-YO03060, DEBIAN-CVE-2026-72815, GHSA-3fxj-6jh8-hvhx, GHSA-qgxv-hqxp-4rcx, GO-2026-5774, MINI-245r-f3qp-vjrx, MINI-25hj-jxq4-xf74, MINI-272r-gcrw-386c, MINI-27xm-rffq-r6r5, MINI-2hrx-jhx3-qrh3, MINI-3254-r8wj-hqmr, MINI-33jj-2f73-wm3q, MINI-33q5-736w-r844, MINI-37qp-r32j-9r6g, MINI-3cpj-p96j-cx7x, MINI-3h9q-qcv3-wg65, MINI-3j3x-p8x2-cwrj, MINI-3jpj-26fw-j4j4, MINI-3wgj-55v3-p345, MINI-493x-j787-vp6m, MINI-4hmx-cvgh-748q, MINI-4j94-rmpx-4f95, MINI-4jr3-h2jx-g24p, MINI-4p5v-258g-hjxw, MINI-54p4-534f-87gw, MINI-5f72-26hr-jfqq, MINI-5whw-qcjm-qhvf, MINI-5xh8-j79x-294p, MINI-627c-6fwj-h329, MINI-64qf-g6vj-wxv4, MINI-65jw-3j45-5c74, MINI-67w7-f2v9-vqv6, MINI-68h9-9j92-89r4, MINI-6f72-54rw-pq35, MINI-6xjh-r333-25ww, MINI-749q-8fjv-3wq7, MINI-77vh-mh3j-p8g6, MINI-7846-cv77-74fr, MINI-7jr9-wcph-gf44, MINI-7mxr-px49-wm9x, MINI-7rgm-8w8h-f45g, MINI-82cf-9p9p-8jx2, MINI-84g2-q839-vqhf, MINI-8956-p9v2-c5fg, MINI-8cvj-xvmh-9jrm, MINI-8fm4-9qgh-49v9, MINI-8hmh-5fc2-55x6, MINI-8pwg-9vq5-4w8j, MINI-8w66-4cv5-35cr, MINI-8x8f-3vw5-j2c6, MINI-963g-gwhw-72v6, MINI-9845-4qh4-64wm, MINI-994w-77g5-9x6q, MINI-9xm3-f32j-32jr, MINI-9xwj-xv25-7mqq, MINI-c82v-w5hr-67gq, MINI-cffv-fx39-x3jr, MINI-f2h2-xrv2-59pj, MINI-fmf6-5v4f-rw3j, MINI-g543-f566-w55c, MINI-gfpg-3h32-6xww, MINI-gv77-g423-hwp2, MINI-hcxq-92w2-243g, MINI-hjcp-xx8m-xw5m, MINI-m846-mg2g-cpf9, MINI-mhcc-98h6-88c4, MINI-p7mr-q6cc-222m, MINI-p7w9-vc9w-jgv6, MINI-ph49-m2rh-gc4r, MINI-ph7r-6p73-fp36, MINI-ph9p-vrc9-pr87, MINI-pj24-42wr-rqfx, MINI-pm7f-cvv9-7mg9, MINI-pmj7-9ccf-2q44, MINI-q3gw-fqjv-4chg, MINI-q743-fr87-xh94, MINI-q763-93x8-g6j4, MINI-qv8r-mmhf-hjhp, MINI-qw8x-gq49-f3f9, MINI-r3m8-m7p4-h38j, MINI-r6jm-v4x9-5pfc, MINI-rpcr-rx38-p876, MINI-rvwg-jq7w-4q5r, MINI-vq65-99f5-q7j5, MINI-w3f2-xp35-7gvf, MINI-w5fp-24jq-wwgm, MINI-wfg8-h69w-3gfv, MINI-wp4q-cqqx-cg59, MINI-wq7r-qg3r-jrx6, MINI-wr9m-p3rr-4h3j, MINI-wrmq-v9f5-pwgr, MINI-x94r-w4r4-mjqp, MINI-xmmq-j7h7-82jw, MINI-xx2m-vh4w-c42f, UBUNTU-CVE-2026-72815, openSUSE-SU-2026:11607-1 ## What is CVE-2026-72815? CVE-2026-72815 is a medium-severity vulnerability in go-chi chi, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description go-chi chi versions >= 5.2.1 and before 5.3.0 contain an IP spoofing vulnerability in the RealIP middleware, which blindly trusts the first (leftmost) value of the X-Forwarded-For HTTP header. A remote attacker can bypass IP-based access control lists and rate-limiting mechanisms, and forge log entries, by supplying a spoofed IP address in the X-Forwarded-For header. The issue is fixed in version 5.3.0. Weakness: CWE-290 (Authentication Bypass by Spoofing) ## Which versions are affected by CVE-2026-72815? 3 open source packages ship an affected version, including github.com/go-chi/chi/v5/middleware and github.com/go-chi/chi/v5. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/go-chi/chi/v5/middleware` | Go | From 5.2.1 | 5.3.0 | | `github.com/go-chi/chi/v5/middleware` | Go | From 5.2.1 | 5.3.0 | | `github.com/go-chi/chi/v5` | Go | From 5.2.1 | 5.3.0 | | `cloudflared` | openSUSE:Tumbleweed | All versions | 2026.8.2-1.1 | ## How do I fix CVE-2026-72815? Upgrade github.com/go-chi/chi/v5/middleware to 5.3.0 or later. ## Is CVE-2026-72815 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72815 exists. Public exploit code: - https://github.com/Saku0512/CVE-2026-72815-poc (github_poc): https://github.com/Saku0512/CVE-2026-72815-poc ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-72815 and fix it if it is affected. What it is: CVE-2026-72815 is a medium-severity vulnerability in go-chi chi, published on 14 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72815 exists. Affected packages and fixed versions: - github.com/go-chi/chi/v5/middleware (Go): affected from 5.2.1; fixed in 5.3.0 - github.com/go-chi/chi/v5/middleware (Go): affected from 5.2.1; fixed in 5.3.0 - github.com/go-chi/chi/v5 (Go): affected from 5.2.1; fixed in 5.3.0 Task: 1. 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. 2. 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. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-72815/ (Markdown: https://insights.sbomify.com/CVE-2026-72815/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72815 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72815 - OSV: https://osv.dev/vulnerability/CVE-2026-72815 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-72815/ Summaries are generated and may contain mistakes; the official description above is the record.