Security Resilience

CVE-2023-3036

Memory Safety in Cloudflare Cfnts ≤ 2023-06-01

Published
14 June 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.022 82th percentile
Risk Priority 66 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-3036 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Cloudflare Cfnts. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 18% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-3040Same vendor: Cloudflare
CVE-2023-2512Same vendor: Cloudflare
CVE-2025-5204Shared CWE-119, CWE-125
CVE-2025-7464Shared CWE-119, CWE-125
CVE-2025-5165Shared CWE-119, CWE-125
CVE-2025-5203Shared CWE-119, CWE-125
CVE-2026-2705Shared CWE-119, CWE-125
CVE-2026-7135Shared CWE-119, CWE-125
CVE-2026-78157Shared CWE-119, CWE-125
CVE-2026-3391Shared CWE-119, CWE-125

Affected Assets

cloudflare
cfnts
≤ 2023-06-01

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-119

Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.

addresses: CWE-119

Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.

addresses: CWE-119

Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.

addresses: CWE-119

Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-01 partial match
blocks

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
blocks

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

PR.PS-06 partial match
blocks

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

removes
removes
removes
removes
removes

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-119, a class-level weakness. Rules are authored against its narrower children: CWE-823.

References