Skip to content
Fencer Intel
high 8.7

CVE-2026-69205 json

Http4s: Ember Transfer-Encoding value parsing (TE.CL / TE.0 request smuggling)

published last mo. modified last mo. also EUVD-2026-79190 , GHSA-9998-894r-fwvr

cvss
8.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s HeaderP.parse uses a case-sensitive substring test for the Transfer-Encoding value and decodes header bytes with the platform default charset. Values such as Chunked are not recognized, values such as notchunked are incorrectly accepted, and Unicode case folding can turn a Kelvin-sign byte sequence into a match when UTF-8 is used. Intermediaries that apply RFC-compliant token and charset rules can therefore disagree with Ember’s Content-Length or zero-length framing, enabling TE.CL or TE.0 request smuggling, access-control bypass, cross-user request hijacking, and cache poisoning on the server path. Response smuggling through an ember-client gateway requires a malicious or compromised upstream. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Patch / fix

  • maven org.http4s:http4s-ember-core_3 0.23.35, 1.0.0-M47
  • maven org.http4s:http4s-ember-core_2.13 0.23.35, 1.0.0-M47
  • maven org.http4s:http4s-ember-core_2.12 0.23.35
  • typelevel http4s 0.23.35, 1.0.0-M47
  • org.http4s http4s-ember-core_2.12 0.23.35
  • org.http4s http4s-ember-core_2.13 0.23.35, 1.0.0-M47
  • org.http4s http4s-ember-core_3 0.23.35, 1.0.0-M47

Is CVE-2026-69205 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
last mo.

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 8.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
GitHub 3.1 8.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven org.http4s:http4s-ember-core_3
<0.23.35
>=1.0.0-M1, <1.0.0-M47
0.23.35
1.0.0-M47
maven org.http4s:http4s-ember-core_2.13
<0.23.35
>=1.0.0-M1, <1.0.0-M47
0.23.35
1.0.0-M47
maven org.http4s:http4s-ember-core_2.12
<0.23.35
0.23.35

Affected products

  • http4s http4s

Classification

Weakness
  • CWE-444 Inconsistent Interpretation of HTTP Requests

References

Sources

Fencer Intel 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.