Vulnerability in swift-nio-http2 (CVE-2026-64785)
Summary
Vulnerability in swift-nio-http2 (CVE-2026-64785). Risk of unauthorized operations or information disclosure. Exploitable via enableOutboundHeaderValidation. Mitigation: upgrade to 48bfd90 or later.
Original description
The description as published by the source.
Summary
SwiftNIO HTTP/2 was missing validation on inbound HEADERS frames that let
CR, LF, NUL, SP and other control characters reach an HTTP/1.1 backend
through NIOHTTP2's HTTP/2-to-HTTP/1 codec, enabling HTTP request smuggling
or response splitting.
Impact
Two related gaps in inbound header validation, against any application
using HTTP2ToHTTP1Codec (or HTTP2FramePayloadToHTTP1Codec) to front an
HTTP/1.1 backend:
Regular header field values were only checked against a forbidden-name
list (connection, transfer-encoding, proxy-connection, keep-alive,
upgrade); the value itself was never inspected. An attacker-controlled
regular header field value containing CR or LF passed validation and, once
serialized as name: value CRLF by the codec, terminated the field early
and injected extra header lines into the outbound HTTP/1.1 message.
Pseudo-header values (:path in particular) were only checked against
CR, LF and NUL. A :path value containing SP serializes into the
request-target of METHOD SP request-target SP HTTP-version CRLF, so a
value like /a HTTP/1.1 produces GET /a HTTP/1.1 HTTP/1.1 — a
parser-differential request line depending on whether a downstream reader
takes the first or last SP-delimited token as the version.
Neither of these is reachable on a stock pipeline: NIOHTTP1's outbound
validator (enableOutboundHeaderValidation, on by default) already rejects
these characters on write. The exposure is pipelines that skip outbound
validation, or any…
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-2026-64785 has been found in swift-nio-http2.
Attackers can target a specific entry point like enableOutboundHeaderValidation over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade swift-nio-http2 to 48bfd90 or later.
If unsure, ask your IT team or search "swift-nio-http2 CVE-2026-64785" on the vendor's site.
CVE-2026-64785 (swift-nio-http2) — CWE-113 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: enableOutboundHeaderValidation / HTTPRequestHead.headers
Patched: 48bfd90 — 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-113) exists in swift-nio-http2. Attackers reach the vulnerable code path via enableOutboundHeaderValidation without authentication.
Check the vendor advisory for the affected versions of swift-nio-http2. Attack surface: enableOutboundHeaderValidation / HTTPRequestHead.headers.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to 48bfd90.
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. Run grep -r 'swift-nio-http2' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'swift-nio-http2' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
swift-nio-http2を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade swift-nio-http2 to 48bfd90ステージング環境で 48bfd90 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。
-
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
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com