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VulnerabilityPublished Updated

CVE-2026-44217: rexxars sse-channel · CRLF Injection

Affects rexxars sse-channelSource CVE Database V5

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Not known to be exploited · CVSS 6.6 Medium : upgrade to 4.0.1 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
6.6Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.0.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 12 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade sse-channel and rexxars/sse-channel to 4.0.1.

Affected software

ProductAffectedFixed in
rexxarssse-channelAffected
  • <4.0.1
Fixed in
  • 4.0.1
npmrexxars/sse-channelpkg:npm/rexxars/sse-channelOther threatsAffected
  • <4.0.1
Fixed in
  • 4.0.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Upgrade to sse-channel version 4.0.1 or later, where this vulnerability is fixed. Since the vendor advisory does not provide additional remediation details, applying this official fix is the recommended action. Patch status is confirmed by the version update note in the description.

Description

sse-channel is an SSE-implementation which can be used to any node.js http request/response stream. Prior to 4.0.1, implementations that allow user-provided values to be passed to event, retry or id fields are susceptible to event spoofing, where an attacker could inject arbitrary messages into the stream. This vulnerability is fixed in 4.0.1.

References

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