CVE-2026-54511 — LogTape is an unobtrusive logging library.¶
Key facts
CVE-2026-54511 is a High (8.6) vulnerability: LogTape is an unobtrusive logging library.. This entry ships a detection-only PoC and a Docker test lab.
| CVE | CVE-2026-54511 |
| Severity | High (8.6) |
| Detection / prevention | — |
| PoC | poc.py |
| Source | 2026/CVE-2026-54511/ |
Details¶
English | 한국어
Description¶
LogTape is an unobtrusive logging library. Prior to 1.3.11, 2.0.14, and 2.1.5, the @logtape/syslog package's escapeStructuredDataValue() function in packages/syslog/src/syslog.ts does not neutralize C0 control characters from U+0000 through U+001F in structured data values, and formatStructuredData() inserts property keys without validating the RFC 5424 SD-NAME grammar. When includeStructuredData is true, an attacker-controlled newline can terminate an RFC 6587 non-transparent TCP syslog frame and make following bytes appear as a forged RFC 5424 record, while a key containing a closing bracket or other forbidden character can terminate or corrupt the structured-data element. Applications that forward attacker-controlled property values or keys can therefore allow forged records with arbitrary hosts, applications, process identifiers, facilities, or severity levels, undermining downstream collector and SIEM integrity. This issue is fixed in versions 1.3.11, 2.0.14, and 2.1.5.
Vulnerability Details¶
| Property | Value |
|---|---|
| CVE ID | CVE-2026-54511 |
| CVSS Score | 8.6 |
Proof of Concept¶
Download¶
# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-54511/poc.py
Usage¶
# Run PoC against target
python3 poc.py --target <TARGET_URL>
# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>
⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.
Test Lab¶
This repository includes a Docker-based test environment with both vulnerable and patched applications.
Quick Start¶
# Clone and navigate to CVE directory
cd CVE-2026-54511
# Start both applications
docker-compose up -d
# Run tests
./run-tests.sh # Linux/Mac
./run-tests.ps1 # Windows PowerShell
Application Endpoints¶
| Application | URL | Status |
|---|---|---|
| Vulnerable App | http://localhost:8080 | Shows vulnerability |
| Patched App | http://localhost:8081 | Demonstrates fix |
Directory Structure¶
├── README.md # English documentation
├── README_KO.md # Korean documentation
├── poc.py # PoC detection script
├── docker-compose.yml # Container orchestration
├── run-tests.sh # Linux/Mac test runner
├── run-tests.ps1 # Windows test runner
├── vulnerable-app/ # Vulnerable version
│ ├── app.py
│ ├── Dockerfile
│ └── requirements.txt
└── patched-app/ # Fixed version
├── app.py
├── Dockerfile
└── requirements.txt
References¶
- https://github.com/dahlia/logtape/commit/7a6e5b9ddf7915edfff78fa129bc17c979b2a623
- https://github.com/dahlia/logtape/releases/tag/1.3.11
- https://github.com/dahlia/logtape/releases/tag/2.0.14
- https://github.com/dahlia/logtape/releases/tag/2.1.5
- https://github.com/dahlia/logtape/security/advisories/GHSA-8h6h-x5pq-56fq
Generated by PoC Generator on 2026-08-30T19:55:10.106908941
Frequently asked questions¶
What is CVE-2026-54511?¶
CVE-2026-54511 is a High (8.6) vulnerability: LogTape is an unobtrusive logging library.. This entry ships a detection-only PoC and a Docker test lab.
How do I detect CVE-2026-54511?¶
Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.
How do I block or mitigate CVE-2026-54511?¶
Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.
For authorized security testing and research only. See the full source and NVD record.