Out of Bounds Slice index in cfnts leads to remote panic

published 2023-06-14 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-43728

cvss: 8.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.2%; EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits: 0; none known

An unchecked read in NTP server in github.com/cloudflare/cfnts prior to commit 783490b https://github.com/cloudflare/cfnts/commit/783490b913f05e508a492cd7b02e3c4ec2297b71 enabled a remote attacker to trigger a panic by sending an NTSAuthenticator packet with extension length longer than the packet contents.

Patch / fix

fixed in 1 links 1

cloudflare cfnts 2023-06-01

github.com/cloudflare/cfnts/security/advisories/GHSA-pwx6-gw47-96cp advisory

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 22 mo ago (2025-01-02)

Exploit prediction

2.24% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.6	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Cloudflare cfnts

Classification

Weakness

CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-125 Out-of-bounds Read

References

github.com /cloudflare/cfnts/security/advisories/GHSA-pwx6-gw47-96cp
patch, third-party-advisory

Sources

CVE List CVE-2023-3036
NVD CVE-2023-3036

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary