Vulnerability in org.http4s:http4s-ember-core_2.13 (CVE-2026-88975)
Summary
Vulnerability in org.http4s:http4s-ember-core_2.13 (CVE-2026-88975). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.0.0-M48 or later.
Original description
The description as published by the source.
Summary
An unauthenticated peer can make Ember's HTTP/2 read loop hold 16 MiB of a single frame in memory on a connection where Ember advertised a 16 KiB limit. The declared length is readable from the frame's first 9 bytes, but it is not compared against SETTINGS_MAX_FRAME_SIZE until the whole payload has been read into a contiguous buffer. That is 1024x amplification per connection, bounded by the protocol's 24-bit length field rather than by any setting, and at the default maxConnections of 1024 it puts about 16 GiB of heap in reach.
Details
H2Frame.RawFrame.fromByteVector (ember-core/.../h2/H2Frame.scala:66-69) reads the length, then refuses to produce a frame until 9 + length bytes are present:
val length = (bv(2) & 0xff) | ((bv(1) & 0xff) << 8) | ((bv(0) & 0xff) << 16)
if (bv.length >= 9 + length) {
readNextFrame in H2Connection.readLoop (H2Connection.scala:246-266) reads that None as "need more" and concatenates further socket reads into one accumulator until it is satisfied.
The only check of an inbound frame against the connection's own SETTINGS_MAX_FRAME_SIZE is in processFrame at H2Connection.scala:534, which cannot run until the frame is assembled. So the value that condemns the frame sits in the accumulator from byte 9 onward and is never consulted. A peer that declares 16777215 and dribbles the payload without finishing gets the same buffering with no reaction at all, since an incomplete frame never reaches processFrame.
RFC 9113 4.2 require…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-88975 has been found in org.http4s:http4s-ember-core_2.13.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade org.http4s:http4s-ember-core_2.13 to 1.0.0-M48 or later.
If unsure, ask your IT team or search "org.http4s:http4s-ember-core_2.13 CVE-2026-88975" on the vendor's site.
CVE-2026-88975 (org.http4s:http4s-ember-core_2.13) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 1.0.0-M48 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-400) exists in org.http4s:http4s-ember-core_2.13.
Check the vendor advisory for the affected versions of org.http4s:http4s-ember-core_2.13.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to 1.0.0-M48.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで org.http4s:http4s-ember-core_2.13 を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade org.http4s:http4s-ember-core_2.13 to 1.0.0-M48ステージング環境で 1.0.0-M48 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com