CVE-2026-54556
- Source
- https://cve.org/CVERecord?id=CVE-2026-54556
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54556.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-54556
- Aliases
- Published
- 2026-08-26T14:10:22.349Z
- Modified
- 2026-08-30T03:30:29.878869238Z
- Severity
-
- 8.2 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
- Summary
- Http4s: HTTP/2 Denial of Service with Ember Backend
- Details
-
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, an unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend with HTTP/2 enabled. The Hpack wrapper in ember-core/shared/src/main/scala/org/http4s/ember/core/h2/Hpack.scala concatenates HEADERS and CONTINUATION frame fragments and decodes them into a single List, but maxHeaderSize accounting does not include indexed headers or HPACK per-header overhead. A small compressed header block can therefore expand into a much larger decoded representation that remains in memory for processing. Servers exposed to untrusted HTTP/2 traffic and clients directed to an untrusted HTTP/2 server are affected, and concurrent malicious connections can exhaust the process heap. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
- Database specific
{ "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54556.json", "cwe_ids": [ "CWE-409" ], "cna_assigner": "GitHub_M" }- References
-
- https://github.com/http4s/http4s/releases/tag/v0.23.35
- https://github.com/http4s/http4s/releases/tag/v1.0.0-M47
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54556.json
- https://github.com/http4s/http4s/security/advisories/GHSA-vmm3-xgcx-67hm
- https://nvd.nist.gov/vuln/detail/CVE-2026-54556
- https://github.com/http4s/http4s/commit/6e8eccd64a6a74ab4811897881e95e0e1b3a818e
Affected packages
Git / github.com/http4s/http4s
Affected ranges
- Type
- GIT
- Repo
- https://github.com/http4s/http4s
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedIntroducedFixedFixedFixedFixed
- Database specific
-
Show details
{ "source": [ "AFFECTED_FIELD", "REFERENCES" ], "extracted_events": [ { "introduced": "0" }, { "fixed": "0.23.35" }, { "introduced": "1.0.0-M1" }, { "fixed": "1.0.0-M46" } ] }