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Medium 5.9Published Sep 15, 2026

CVE-2026-69212Http4s: FollowRedirect middleware leaks credentials over https->http same-authority redirect

Updated under an hour ago ()

Does this affect you?

It affects http4s. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The FollowRedirect client middleware strips Authorization and Cookie headers only when a redirect changes authority, but authority comparison excludes the URI scheme. A same-authority redirect from HTTPS to HTTP therefore preserves credentials and transmits them over a plaintext connection. An attacker who can induce the downgrade and observe the network can capture those sensitive headers from applications using FollowRedirect. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

CVSS
5.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE)
CWE-200, CWE-319
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
Sep 15, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
http4s http4s
http4s:http4s (from the name)
before 0.23.35; from 1.0.0-M1, < 1.0.0-M47
CNA record

References

  • x-refsource-confirm
  • x-refsource-misc
  • x-refsource-misc
  • x-refsource-misc

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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