Skip to main content
Public proof of conceptFix available

CVE-2023-39325

A public proof of concept exists; no exploitation attested.

  • Published2023-10-11
  • WeaknessCWE-770

Am I 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

A malicious HTTP/2 client which rapidly creates requests and immediately resets them can cause excessive server resource consumption. While the total number of requests is bounded by the http2.Server.MaxConcurrentStreams setting, resetting an in-progress request allows the attacker to create a new request while the existing one is still executing. With the fix applied, HTTP/2 servers now bound the number of simultaneously executing handler goroutines to the stream concurrency limit (MaxConcurrentStreams). New requests arriving when at the limit (which can only happen after the client has reset an existing, in-flight request) will be queued until a handler exits. If the request queue grows too large, the server will terminate the connection. This issue is also fixed in golang.org/x/net/http2 for users manually configuring HTTP/2. The default stream concurrency limit is 250 streams (requests) per HTTP/2 connection. This value may be adjusted using the golang.org/x/net/http2 package; see the Server.MaxConcurrentStreams setting and the ConfigureServer function.

Timeline

dates in UTC
  1. 2023-10-1122:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-39325?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-39325?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Fedoraproject fedora
BranchAffectedFixed in
37.x= 37no fix published
38.x= 38no fix published
39.x= 39no fix published
Go
BranchAffectedFixed in
1.21≥ 1.21.0, < 1.21.31.21.3
1.20≥ 1.20.0, < 1.20.101.20.10
Golang http2
BranchAffectedFixed in
0.17< 0.17.00.17.0

2 more products in the sources.

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.

Vendor advisories

  • CVE-2023-39325 Red Hat Product Security6,209 products fixed · 186 known affected

    golang: net/http, x/net/http2: rapid stream resets can cause excessive work (CVE-2023-44487)

    openshift-builds-triggers-container as a component of Builds for Red Hat OpenShift · openshift-builds/openshift-builds-controller-rhel8 as a component of Builds for Red Hat OpenShift · openshift-builds/openshift-builds-rhel8-operator as a component of Builds for Red Hat OpenShift · +183 more

  • RHSA-2026:8322 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: rhc security update

  • RHSA-2025:4240 Red Hat Product Security18 products fixed

    Red Hat Security Advisory: Updated 6.1 container image is now available in the Red Hat Ecosystem Catalog.

  • RHSA-2025:1116 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.13.55 bug fix and security update

  • RHSA-2025:0832 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.12.72 bug fix and security update

  • RHSA-2025:0014 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: OpenShift Container Platform 4.12.71 bug fix and security update

217 more advisories

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2026:8322 · 13 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. Vendor fix Red Hat Product Security RHSA-2025:4240 · 18 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/2789521 For supported configurations, refer to: https://access.redhat.com/articles/1548993
  3. Vendor fix Red Hat Product Security RHSA-2025:1116 · 2 productsFor OpenShift Container Platform 4.13 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.13/release_notes/o…
  4. Vendor fix Red Hat Product Security RHSA-2025:0832 · 1 productFor OpenShift Container Platform 4.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.12/release_notes/ocp-4-1…
  5. Vendor fix Red Hat Product Security RHSA-2025:0014 · 1 productFor OpenShift Container Platform 4.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.12/release_notes/o…
  6. Vendor fix Red Hat Product Security RHSA-2024:10523 · 1 productFor OpenShift Container Platform 4.14 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this asynchronous errata update: https://docs.openshift.com/container-platform/4.14/release_notes/o…

Advisories and patches

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedeilam-cell/cve-test-coredns-fork
PoC-in-GitHub

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • NVDweakness (CWE)CWE-770read 2026-10-23
  • FIRST EPSSEPSS score3.8 %2026-10-22
  • PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2023-10-11
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2023-39325?

A malicious HTTP/2 client which rapidly creates requests and immediately resets them can cause excessive server resource consumption. While the total number of requests is bounded by the http2.Server.MaxConcurrentStreams setting, resetting an in-progress request allows the attacker to create a new request while the existing one is still executing. With the fix applied, HTTP/2 servers now bound the number of simultaneously executing handler goroutines to the stream concurrency limit (MaxConcurrentStreams). New requests arriving when at the limit (which can only happen after the client has reset an existing, in-flight request) will be queued until a handler exits. If the request queue grows too large, the server will terminate the connection. This issue is also fixed in golang.org/x/net/http2 for users manually configuring HTTP/2. The default stream concurrency limit is 250 streams (requests) per HTTP/2 connection. This value may be adjusted using the golang.org/x/net/http2 package; see the Server.MaxConcurrentStreams setting and the ConfigureServer function.

Is CVE-2023-39325 actively exploited?

Active exploitation of CVE-2023-39325 has not been confirmed. Its EPSS score was 3.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2023-39325?

CVE-2023-39325 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Running Go? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, October 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database