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Fencer Vulns
medium 5.9

CVE-2026-69201 json

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

published 2026-09-15 54 d ago modified 2026-09-16 53 d ago also GHSA-crq5-92j2-j7wv , EUVD-2026-79177

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, ResourceService and WebjarService decode each URL path segment but reject only segments exactly equal to an empty string, a dot, or two dots. A request containing percent-encoded slash or backslash separators can turn an accepted segment into a parent-directory traversal after decoding, allowing access to classpath or WebJar resources outside the configured base when a directory-backed classpath is served and the backend preserves the encoded separator. The patch rejects decoded segments containing slash or backslash in ResourceService and WebjarService, and applies the same guard to the non-exploitable FileService for consistency. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Patch / fix

  • maven org.http4s:http4s-server_2.12 0.23.35
  • maven org.http4s:http4s-server_2.13 0.23.35, 1.0.0-M47
  • maven org.http4s:http4s-server_3 0.23.35, 1.0.0-M47

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
54 d ago

Exploit prediction

0.76% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
maven org.http4s:http4s-server_2.12
<0.23.35
0.23.35
maven org.http4s:http4s-server_2.13
<0.23.35
>=1.0.0-M1, <1.0.0-M47
0.23.35
1.0.0-M47
maven org.http4s:http4s-server_3
<0.23.35
>=1.0.0-M1, <1.0.0-M47
0.23.35
1.0.0-M47

Affected products

  • http4s http4s

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.