All vulnerabilities
CVE-2026-78667

Lack of limit on size of parsed Range headers in net/http

Go standard library net/http
Open in ThreatlineRecord JSON
CVSS
7.5High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.38%Chance of exploitation activity in the next 30 days, higher than 30% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in1.26.9Also 1.27.2CVE List
Published8 Oct 2026Updated 9 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

When parsing a Range header containing a large number of small ranges, FileServer(FS), ServeContent, and ServeFile(FS) can consume an excessive amount of CPU.

Text from CVE List

Affected versions 2

  • net/httpaffected: all versions before 1.26.9CVE List
  • net/httpaffected: 1.27.0-0 before 1.27.2CVE List

References 4