# CVE-2026-100725: http4k before 6.48.0.0 Cookie Scoping Bypass via BasicCookieStorage > Attackers can steal session cookies from one origin and send them to another due to missing cookie scoping checks in the http4k client library. - **Severity:** High 8.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/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:** No - **Published:** 27 Sep 2026 - **Updated:** 29 Oct 2026 - **Also known as:** GHSA-jggj-q26h-3m3c, GHSA-pr33-38xx-6r26 ## What is CVE-2026-100725? CVE-2026-100725 is a high-severity vulnerability in http4k, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description http4k (Maven artifact org.http4k:http4k-core) before 6.48.0.0, 5.42.0.0, and 4.51.0.0 ships a BasicCookieStorage (client-side cookie store used by ClientFilters.Cookies) that does not enforce RFC 6265 scoping rules for the cookie domain, path, and Secure attributes. When a single BasicCookieStorage instance is used to talk to more than one origin or scheme, cookies stored for one origin can be sent to other origins, and cookies marked Secure can be sent over plain HTTP, potentially disclosing session cookies or other sensitive values to unauthorized hosts or network observers. Clients that use a storage instance for a single origin are not affected. Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) ## Which versions are affected by CVE-2026-100725? 6 open source packages ship an affected version, including org.http4k:http4k-core. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `org.http4k:http4k-core` | Maven | All versions | 4.51.0.0 | | `org.http4k:http4k-core` | Maven | All versions | 4.51.0.0 | | `org.http4k:http4k-core` | Maven | From 5.0.0.0 | 5.42.0.0 | | `org.http4k:http4k-core` | Maven | From 5.0.0.0 | 5.42.0.0 | | `org.http4k:http4k-core` | Maven | From 6.0.0.0 | 6.48.0.0 | | `org.http4k:http4k-core` | Maven | From 6.0.0.0 | 6.48.0.0 | ## How do I fix CVE-2026-100725? Upgrade org.http4k:http4k-core to a fixed version for your release line: 4.51.0.0, 5.42.0.0 or 6.48.0.0. ## Is CVE-2026-100725 being exploited? There is no known exploitation of CVE-2026-100725 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-100725 and fix it if it is affected. What it is: CVE-2026-100725 is a high-severity vulnerability in http4k, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-100725 in the wild and no public exploit code. Affected packages and fixed versions: - org.http4k:http4k-core (Maven): affected all versions; fixed in 4.51.0.0 - org.http4k:http4k-core (Maven): affected all versions; fixed in 4.51.0.0 - org.http4k:http4k-core (Maven): affected from 5.0.0.0; fixed in 5.42.0.0 - org.http4k:http4k-core (Maven): affected from 5.0.0.0; fixed in 5.42.0.0 - org.http4k:http4k-core (Maven): affected from 6.0.0.0; fixed in 6.48.0.0 - org.http4k:http4k-core (Maven): affected from 6.0.0.0; fixed in 6.48.0.0 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-2026-100725/ (Markdown: https://insights.sbomify.com/CVE-2026-100725/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100725 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100725 - OSV: https://osv.dev/vulnerability/CVE-2026-100725 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-100725/ Summaries are generated and may contain mistakes; the official description above is the record.