CVE-2025-65637
A denial-of-service vulnerability exists in github.com/sirupsen/logrus when using Entry.Writer() to log a single-line payload larger than 64KB without newline characters. Due to limitations in the internal bufio.Scanner, the read fails with "token too long" and the writer pipe is closed, leaving Writer() unusable and causing application unavailability (DoS). This affects versions < 1.8.3, 1.9.0, and 1.9.2. The issue is fixed in 1.8.3, 1.9.1, and 1.9.3+, where the input is chunked and the writer continues to function even if an error is logged.
02 / AFFECTED SOFTWARE
Affected packages
7 explicit affected versions
2 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
A denial-of-service vulnerability exists in github.com/sirupsen/logrus when using Entry.Writer() to log a single-line payload larger than 64KB without newline characters. Due to limitations in the internal bufio.Scanner, the read fails with "token too long" and the writer pipe is closed, leaving Writer() unusable and causing application unavailability (DoS). This affects versions < 1.8.3, 1.9.0, and 1.9.2. The issue is fixed in 1.8.3, 1.9.1, and 1.9.3+, where the input is chunked and the writer continues to function even if an error is logged.
A denial-of-service vulnerability exists in github.com/sirupsen/logrus when using Entry.Writer() to log a single-line payload larger than 64KB without newline characters. Due to limitations in the internal bufio.Scanner, the read fails with "token too long" and the writer pipe is closed, leaving Writer() unusable and causing application unavailability (DoS). This affects versions < 1.8.3, 1.9.0, and 1.9.2. The issue is fixed in 1.8.3, 1.9.1, and 1.9.3+, where the input is chunked and the writer continues to function even if an error is logged.
Logrus is vulnerable to DoS when using Entry.writerScanner in github.com/sirupsen/logrus
05 / REFERENCES
Further evidence
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/65xxx/CVE-2025-65637.json
- https://github.com/mjuanxd/logrus-dos-poc
- https://github.com/mjuanxd/logrus-dos-poc/blob/main/README.md
- https://github.com/sirupsen/logrus/issues/1370
- https://github.com/sirupsen/logrus/pull/1376
- https://github.com/sirupsen/logrus/releases/tag/v1.8.3
- https://github.com/sirupsen/logrus/releases/tag/v1.9.1
- https://github.com/sirupsen/logrus/releases/tag/v1.9.3
- https://nvd.nist.gov/vuln/detail/CVE-2025-65637
- https://security.snyk.io/vuln/SNYK-GOLANG-GITHUBCOMSIRUPSENLOGRUS-5564391
- https://github.com/sirupsen/logrus
- https://github.com/sirupsen/logrus/commit/6acd903758687c4a3db3c11701e6c414fcf1c1f7
- https://github.com/advisories/GHSA-4f99-4q7p-p3gh