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CVE-2023-6992

17
FAUCET Score

CVE-2023-6992 describes memory corruption vulnerabilities, specifically heap-based buffer overflows and improper input validation, within Cloudflare's custom zlib library affecting its deflation algorithm. A local attacker could exploit these flaws during compression with a specially crafted file, leading to a denial of service. The vulnerability has a CVSS score of 5.5 (Medium), indicating a low attack complexity and requiring local access, with the primary impact being high availability loss. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 2023-11-16CPE matchmatch criteria
cpe:2.3:a:cloudflare:zlib:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.0MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
LOW
Exploitability Score
1.4
Impact Score
2.5
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.24%
Probability of exploitation in next 30 days
EPSS Percentile
14.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0024 is in the 64th percentile among its peer group of 15,937 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

github_advisorypatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: 16825-17084Fixed in: 2.5.12-4
microsoftpatch availablevia msrc
Product: 16826-17084Fixed in: 1.3.8-1
microsoftpatch availablevia msrc
Product: azl3 teckit 2.5.12-4 on Azure Linux 3.0Fixed in: 2.5.12-4
microsoftpatch availablevia msrc
Product: azl3 fltk 1.3.8-1 on Azure Linux 3.0Fixed in: 1.3.8-1
nodejspatch availablevia llm_extracted
Fixed in: 25.4.0

Vendor Advisories (2)

nodejsllm-nodejs-9e1762a1939f642dCRITICAL

Third-Party Package Updates in Splunk AppDynamics On-Premises Enterprise Console - August 2025

Aug 6, 2025
microsoft2024-Jan/CVE-2023-6992

Memory corruption issues is Cloudflare zlib implementation

Jan 9, 2024

References

github.com / cloudflare/zlib
Product
github.com / cloudflare/zlib/security/advisories/GHSA-vww9-j87r-4cqh
PatchThird Party Advisory