HighCVE-2026-84445

    Google Grpc-go: Improper Validation of Array Index (CVE-2026-84445)

    Published Last modified Sources: Red Hat, SUSE, BSI, CVE.org, Hersteller, OSV, Msrc Update Guide

    What is affected, what to do

    A flaw was found in gRPC-Go. Servers created with xds.NewGRPCServer() can be exploited by a remote client sending a malformed RPC request that lacks the required :authority or Host headers.

    Update Google Grpc-go to version 1.82.2.

    Affected
    • Google Grpc-go gte 1.83.0, < 1.83.2..*
    • Google Grpc-go lt *..1.82.2
    Fixed in
    • Google Grpc-go 1.82.2

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    8.7

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v4

    8.7

    CVSS v4

    Severity High on the scale from 0 to 10.

    Source: Red Hat, SUSE, BSI, CVE.org, Hersteller, OSV, Msrc Update Guide

    0.6 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 50.6

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    91.06 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    8.7 Methodology
    CVSS v4

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    8.7
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.6 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    50.6
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 14 September 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-129, CWE-248

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    A flaw was found in gRPC-Go. Servers created with xds.NewGRPCServer() can be exploited by a remote client sending a malformed RPC request that lacks the required :authority or Host headers. This can trigger an index-out-of-bounds panic, leading to the termination of the entire server process and a Denial of Service (DoS). In some deployments, this attack can be unauthenticated.

    Source: redhat_csaf, suse_csaf, BSI WID Portal, BSI CSAF, NVD (NIST), CVE.org (MITRE), GitHub Security Advisories, OSV (Open Source Vulnerabilities), cvelistv5, Microsoft Security Update Guide

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    grpcgrpc-go
    • < 1.82.2
    • ≥ 1.83.0, < 1.83.2
    • 1.82.2
    • —
    Red HatEnterprise Linux
    • 9
    • —
    gogoogle.golang.org/grpc
    • 1.84.0-dev
    • 1.83.0
    • 1.85.0-dev
    • —
    • —
    • —

    Vendors and products

    Weakness classes (CWE)

    • CWE-129Improper Validation of Array Index

      Variant

      The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.

      Entry at MITRE CWE-129

    • CWE-248Uncaught Exception

      Base

      An exception is thrown from a function, but it is not caught.

      Entry at MITRE CWE-248

    References & sources

    • github.comgrpc/grpc-go/security/advisories/GHSA-2v4p-qf9q-27wjweb, x_refsource_CONFIRM
    • github.comgrpc/grpc-go/issues/9354web, x_refsource_MISC
    • github.comgrpc/grpc-go/pull/9365web, x_refsource_MISC
    • github.comgrpc/grpc-go/pull/9366web, x_refsource_MISC
    • github.comgrpc/grpc-go/pull/9367web, x_refsource_MISC
    • github.comgrpc/grpc-go/commit/3822494d8ea03b992c089fd2a195f041762fffb7web, x_refsource_MISC
    • github.comgrpc/grpc-go/commit/8668b69c167df908b6b3666dcbf40992b9e932a4web, x_refsource_MISC
    • github.comgrpc/grpc-go/commit/93e31b48545e2a8aaeb6e06b47fb249f94e6297fweb, x_refsource_MISC
    • github.comgrpc/grpc-gopackage
    • github.comgrpc/grpc-go/releases/tag/v1.82.2web, x_refsource_MISC
    • github.comgrpc/grpc-go/releases/tag/v1.83.2web, x_refsource_MISC
    • NVD (NIST)vuln/detail/CVE-2026-84445advisory

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. ReceivedGitHub

      CVSS V4.0: AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

      Weakness type: CWE-129, CWE-248

      Description added or changed

      Show 15 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      gRPC-Go is the Go language implementation of gRPC. Prior to 1.82.2 and 1.83.2, servers created with xds.NewGRPCServer() allow internal/transport/http2_server.go to accept an RPC containing neither the :authority header nor the Host header, while RouteAndProcess in internal/xds/server/routing.go assumes that an authority value exists and indexes the empty slice. A remote client that can complete transport connection establishment can trigger an index-out-of-bounds panic that is not recovered by the per-RPC goroutine and terminates the entire server process. In insecure or ordinary TLS deployments the request can be unauthenticated, while strict mTLS or ALTS deployments require valid transport credentials before the malformed RPC can reach the interceptor. This issue is fixed in versions 1.82.2 and 1.83.2.
      CVSSadded
      —
      AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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
      Weakness type (CWE)added
      —
      CWE-129
      Weakness type (CWE)added
      —
      CWE-248
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/84xxx/CVE-2026-84445.json">CVE-2026-84445</a>
      Referenceadded
      —
      https://github.com/grpc/grpc-go/commit/3822494d8ea03b992c089fd2a195f041762fffb7
      Referenceadded
      —
      https://github.com/grpc/grpc-go/commit/8668b69c167df908b6b3666dcbf40992b9e932a4
      Referenceadded
      —
      https://github.com/grpc/grpc-go/commit/93e31b48545e2a8aaeb6e06b47fb249f94e6297f
      Referenceadded
      —
      https://github.com/grpc/grpc-go/issues/9354
      Referenceadded
      —
      https://github.com/grpc/grpc-go/pull/9365
      Referenceadded
      —
      https://github.com/grpc/grpc-go/pull/9366
      Referenceadded
      —
      https://github.com/grpc/grpc-go/pull/9367
      Referenceadded
      —
      https://github.com/grpc/grpc-go/releases/tag/v1.82.2
      Referenceadded
      —
      https://github.com/grpc/grpc-go/releases/tag/v1.83.2
      Referenceadded
      —
      https://github.com/grpc/grpc-go/security/advisories/GHSA-2v4p-qf9q-27wj

      Source identifier: security-advisories@github.com

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: yes

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-84445","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-09-14T16:36:00.554548Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

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