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MEDIUMpublic exploit

CVE-2026-69212

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

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.

Published Updated Sources: cvelistV5, GitHub_M

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Exploit code

public exploit, none observed

EPSS

0%

chance of exploitation in 30 days

Affects

http4s

http4s

CVSS base

5.9

MEDIUM

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

http4s

Products (1)

http4s

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
5.9CVSS 3.1MEDIUM——cvelistV5

Weakness & attack patterns

  • CWE-200
  • CWE-319

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1562.003Impair Defenses: Impair Command History Logging
  • T1574.006Hijack Execution Flow: Dynamic Linker Hijacking
  • T1574.007Hijack Execution Flow: Path Interception by PATH Environment Variable

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Indexed by

poc in github

References

4 on the record

Elsewhere on this site

  • http4severy CVE for this vendor
  • CWE-200other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.