CVE-2026-58055
No exploitation reported by the sources we read.
- Published2026-06-28
- WeaknessCWE-444
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
nghttp2's nghttpx proxy through 1.69.0 forwards an HTTP/1.1 Upgrade request that also carries a Content-Length header and body onto reusable keep-alive backend connections, re-adding the Upgrade and Connection headers while passing Content-Length verbatim. A backend that resolves the resulting ambiguous message in the attacker's favor enables HTTP request/response smuggling and cross-client response-queue poisoning.
Timeline
dates in UTC- 2026-06-2802:16CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-58055?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-58055?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.69 | ≤ 1.69.0 | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Packages
- libnghttp2AlmaLinux:10all versions · fixed in 1.68.0-3.el10_2.2and 2 other packages
- libnghttp2AlmaLinux:9all versions · fixed in 1.43.0-6.el9_8.2and 2 other packages
- libnghttp2AlmaLinux:8all versions · fixed in 1.33.0-6.el8_10.3and 2 other packages
Vendor advisories
nghttp2: nghttp2: HTTP Request/Response Smuggling and Response-Queue Poisoning via ambiguous HTTP/1.1 Upgrade requests
nodejs as a component of Red Hat Enterprise Linux 10 · nodejs-devel as a component of Red Hat Enterprise Linux 10 · nodejs-docs as a component of Red Hat Enterprise Linux 10 · +53 more
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.17.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
23 more advisories
Fix
- Vendor fix Red Hat Product Security RHSA-2026:86895 · 16 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
- Vendor fix Red Hat Product Security RHSA-2026:82888 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images are different depending on the installation plan approval policy you used when installing the cert-manager Operator for Red Hat OpenShift. - If t…
- Vendor fix Red Hat Product Security RHSA-2026:66018 · 5 productsThe container images provided by this release, apart from the installer, should be deployed using rhui-installer utility. See the official documentation for more details.
- Workaround from the vendor Red Hat Product Security RHSA-2026:86895 · 16 productsConfigure your WAF or load balancer to drop incoming HTTP/1.1 requests that contain both Upgrade and Content-Length headers. This blocks the malformed traffic at the edge before it can reach the vulnerable proxy without impacting legitimate users.
Advisories and patches
- github.comPatch
- www.vulncheck.comPatch
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVE recordread 2026-10-23
- CISA-ADPSSVC decisionnone2026-06-29
- OpenCVESSVC decisionnone—
- CNACVSS 4.06.3read 2026-10-23
- CNACVSS 3.15.4read 2026-10-23
- CNAweakness (CWE)CWE-444read 2026-10-23
- FIRST EPSSEPSS score0.3 %2026-10-23
- OSVaffected packages—
- Microsoft MSRCadvisory—
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
- CVSS 4.0 vector
- CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Published
- 2026-06-28
- Last Modified
- 2026-06-30
- NVD status
- Analyzed
- MSRC Title
- nghttp2 nghttpx - HTTP Request/Response Smuggling via Upgrade Request with Content-Length
Frequently asked questions
What is CVE-2026-58055?
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What is the CVSS score for CVE-2026-58055?
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.