Vulnerability · Published Aug 26, 2026 · Assigned by GitHub_M

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

High 8.6

In plain English

A high-severity security flaw in logtape from dahlia. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.6High

Exploit odds (30 days)0.5%top 58.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	@logtape/syslog	2.1.5	GHSA-8h6h-x5pq-56fq
npm	@logtape/syslog	2.0.14	GHSA-8h6h-x5pq-56fq
npm	@logtape/syslog	1.3.11	GHSA-8h6h-x5pq-56fq

Affected products (as reported)

Vendor	Product	Versions
dahlia	logtape	< 1.3.11>= 2.0.0, < 2.0.14>= 2.1.0, < 2.1.5

Weakness: CWE-93, CWE-117 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

References

https://github.com/dahlia/logtape/security/advisories/GHSA-8h6h-x5pq-56fq x_refsource_CONFIRM
https://github.com/dahlia/logtape/commit/7a6e5b9ddf7915edfff78fa129bc17c979b2a623 x_refsource_MISC
https://github.com/dahlia/logtape/releases/tag/1.3.11 x_refsource_MISC
https://github.com/dahlia/logtape/releases/tag/2.0.14 x_refsource_MISC
https://github.com/dahlia/logtape/releases/tag/2.1.5 x_refsource_MISC