CVE-2026-43973Network attack vector

Client node crash via unbounded response buffering

Published Jun 8, 2026 · Updated Jun 8, 2026

Uncontrolled resource consumption in Gun 1.0.0 through 2.3.0 allows remote attackers to crash the client node via partial HTTP/1.1 responses. The head, body_chunked, and body_trailer clauses in gun_http:handle/5 repeatedly concatenate TCP data into the connection buffer without enforcing a size ceiling. Exploitation requires a Gun client to connect to a malicious or compromised server; one incomplete response can exhaust node-wide memory and cause an out-of-memory crash.

CVSS severity8.7
High
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in Gun 1.0.0 through 2.3.0 allows remote attackers to crash the client node via partial HTTP/1.1 responses. The head, body_chunked, and body_trailer clauses in gun_http:handle/5 repeatedly concatenate TCP data into the connection buffer without enforcing a size ceiling. Exploitation requires a Gun client to connect to a malicious or compromised server; one incomplete response can exhaust node-wide memory and cause an out-of-memory crash.

The record

CVE
CVE-2026-43973
Published
Jun 8, 2026
Updated
Jun 8, 2026
Vendor
Nine Nines
Product
Gun
Classifications
CWE-770, CAPEC-130, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=1.0.0 <2.4.0
  2. Affected versionversion=11dfe71f4b9aedaaedea2ad3b2f32fd006a8480f <f3e7e0568b3c4cf9fa4bea79d5116e67ce76ad25

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Nine Nines · Gunversion=1.0.0 <2.4.0; version=11dfe71f4b9aedaaedea2ad3b2f32fd006a8480f <f3e7e0568b3c4cf9fa4bea79d5116e67ce76ad25

Published CVSS scores

7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7Erlang Ecosystem FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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 exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CAPEC-130Excessive Allocation
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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