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Fencer Vulns
high 8.6

CVE-2026-54511 json

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

published 2026-08-26 2 mo ago modified 2026-09-09 1 mo ago also GHSA-8h6h-x5pq-56fq , EUVD-2026-66563

cvss
8.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

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.

Patch / fix

  • npm @logtape/syslog 1.3.11, 2.0.14, 2.1.5

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
2 mo ago

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
GitHub 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm @logtape/syslog
>=2.1.0, <2.1.5
>=2.0.0, <2.0.14
<1.3.11
2.1.5
2.0.14
1.3.11

Affected products

  • dahlia logtape

Classification

Weakness
  • CWE-93 Improper Neutralization of CRLF Sequences
  • CWE-117 Improper Output Neutralization for Logs

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.