CVE-2023-39325Known exploitationPublic exploitNetwork attack vector

Service interruption via unbounded rapid-reset handlers

Published Oct 11, 2023 · Updated Feb 13, 2025

Resource exhaustion in Go net/http and x/net/http2 allows remote attackers to interrupt HTTP/2 service via rapid stream resets. The server releases a reset stream's concurrency slot while its handler goroutine continues, so repeated HEADERS and RST_STREAM frames create handlers beyond MaxConcurrentStreams. Any reachable HTTP/2 server using affected Serve paths is exposed; accumulated handlers consume server resources and deny legitimate requests.

CVSS severity7.5
High
EPSS probability3.80%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Go net/http and x/net/http2 allows remote attackers to interrupt HTTP/2 service via rapid stream resets. The server releases a reset stream's concurrency slot while its handler goroutine continues, so repeated HEADERS and RST_STREAM frames create handlers beyond MaxConcurrentStreams. Any reachable HTTP/2 server using affected Serve paths is exposed; accumulated handlers consume server resources and deny legitimate requests.

The record

CVE
CVE-2023-39325
Published
Oct 11, 2023
Updated
Feb 13, 2025
Vendor
Go standard library
Product
net/http
Classifications
CWE-400, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2023Exploitation reportedHTTP/2 Rapid Reset attack campaign
  2. Oct 11, 2023CVE publishedPublication date reported by the CVE source.
  3. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.20.10
  2. Affected versionversion=1.21.0-0 <1.21.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Go standard library · net/httpversion=0 <1.20.10; version=1.21.0-0 <1.21.3
golang.org/x/net · golang.org/x/net/http2version=0 <0.17.0

Published CVSS scores

7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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