How severe is CVE-2026-69201?

CVE-2026-69201 has a CVSS score of 5.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-69201?

CVE-2026-69201 affects the following packages: org.http4s:http4s-server_2.12 (Maven), org.http4s:http4s-server_2.13 (Maven), org.http4s:http4s-server_3 (Maven), org.http4s:http4s-server_3 (Maven), org.http4s:http4s-server_2.13 (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-69201?

Update org.http4s:http4s-server_2.12 to 0.23.35 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-69201 is resolved across your whole dependency graph.

How do I detect CVE-2026-69201 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.http4s:http4s-server_2.12, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-69201 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2026-69201 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-69201 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-69201?

CVE-2026-69201 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 55th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-69201?

CVE-2026-69201 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-69201 published, and has it been updated?

CVE-2026-69201 was published on September 15, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2026-69201 — http4s-server_2.12

MEDIUMFix: http4s/http4s@bcd99cd

CVE-2026-69201 is a medium-severity (CVSS 5.9) Path Traversal vulnerability in org.http4s:http4s-server_2.12. A fix is available for org.http4s:http4s-server_2.12 — see the affected versions and patch details below.

Http4s: ResourceService and Webjar Service path escape via percent-encoded separators

Also known asGHSA-crq5-92j2-j7wv

Published

Sep 15, 2026

Updated

Oct 28, 2026

Affected

5 pkgs

Patched

5 / 5

Exploits

None indexed

Exploitation data as of Oct 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-69201.

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs55th percentile — riskier than 55% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-69201 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 398,142 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

5 pkgs affected

☕org.http4s:http4s-server_2.12☕org.http4s:http4s-server_2.13☕org.http4s:http4s-server_3☕org.http4s:http4s-server_3☕org.http4s:http4s-server_2.13

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

The static content handlers ResourceService and WebjarService URL decode each path segment and then reject only segments that are exactly "", ".", or "..". A percent-encoded separator (%2F) lets an attacker smuggle a ../ segment past that filter and escape the configured base, reading resources that should not be public.

On Windows, a similar attack exists with (%5C).

Impact

Disclosure of classpath or webjar resources outside the configured base.

Preconditions

Application uses ResourceService (with a non-root base path) or WebjarService
At least one classpath entry is served from a directory (e.g. sbt run, exploded .war)
Backend forwards %2F/%5C without normalizing (e.g., Ember, Blaze)

Fixes

The patch rejects any decoded path segment containing / (%2F) or \ (%5C) with a 400 Bad Request in ResourceService and WebjarService.

FileService was not exploitable, but the same guards are applied for consistency and to remove its reliance on path normalization.

Workarounds

Deploy as a fat jar, with no filesystem directories on the classpath.
Front the service with a proxy that rejects/normalizes %2F and %5C in the request path.

Affected Packages

5 total 5 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.http4s:http4s-server_2.12`	all versions	0.23.35`org.http4s:http4s-server_2.12:0.23.35`
☕Maven	`org.http4s:http4s-server_2.13`	all versions	0.23.35`org.http4s:http4s-server_2.13:0.23.35`
☕Maven	`org.http4s:http4s-server_3`	all versions	0.23.35`org.http4s:http4s-server_3:0.23.35`
☕Maven	`org.http4s:http4s-server_3`	≥ 1.0.0-M1&&< 1.0.0-M47	1.0.0-M47`org.http4s:http4s-server_3:1.0.0-M47`
☕Maven	`org.http4s:http4s-server_2.13`	≥ 1.0.0-M1&&< 1.0.0-M47	1.0.0-M47`org.http4s:http4s-server_2.13:1.0.0-M47`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.http4s:http4s-server_2.12, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.http4s:http4s-server_2.12 to 0.23.35 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-69201 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

The static content handlers `ResourceService` and `WebjarService` URL decode each path segment and then reject only segments that are exactly `""`, `"."`, or `".."`. A percent-encoded separator (`%2F`) lets an attacker smuggle a `../` segment past that filter and escape the configured base, reading resources that should not be public. On Windows, a similar attack exists with (`%5C`). ## Impact Disclosure of classpath or webjar resources outside the configured base. ## Preconditions - Application uses `ResourceService` (with a non-root base path) or `WebjarService` - At least one classpat