Vulnerability in Rexxars Eventsource-Encoder
CVE-2026-44214
eventsource-encoder encodes events as well-formed EventSource/Server Sent Event (SSE) messages. Prior to 1.0.2, eventsource-encoder does not sanitize the event or id fields of an EventSourceMessage before serializing them. An attacker who controls either field can inject arbitrary Server-Sent Events line terminators (\n, \r, or \r\n) and thereby forge additional SSE fields or entire messages on the stream. This vulnerability is fixed in 1.0.2.
Vulnerability class: CRLF Injection
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (22.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 23rd percentile — 22.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- Rexxars Eventsource-Encoder — versions < 1.0.2
Weakness classification (CWE)
References
- github.com/rexxars/eventsource-encoder/security/advisories/GHSA-m9g3-3g99-mhpx (Exploit, Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-44214?
- CVE-2026-44214 is a medium-severity vulnerability in Rexxars Eventsource-Encoder, classified under CRLF Injection. CVSS score: 5.8/10. Published 2026-05-26.
- How severe is CVE-2026-44214?
- Medium severity. CVSS v3 base score is 5.8 out of 10.