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Fencer Vulns
medium 6.5

CVE-2018-19791 json

The server in LiteSpeed OpenLiteSpeed before 1.5.0 RC6 does not correctly handle requests for byte sequences, allowing an attacker to ampli…

published 2018-12-03 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-11470

cvss
6.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits
0
none known

Summary

The server in LiteSpeed OpenLiteSpeed before 1.5.0 RC6 does not correctly handle requests for byte sequences, allowing an attacker to amplify the response size by requesting the entire response body repeatedly, as demonstrated by an HTTP Range header value beginning with the "bytes=0-,0-" substring.

Patch / fix

  • litespeedtech openlitespeed 1.5.0

Exploit prediction

1.24% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/litespeedtech/openlitespeed/issues/117 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 6.5 CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.0 AV:N/AC:L/Au:S/C:N/I:N/A:P

Classification

Weakness
  • CWE-20 Improper Input Validation

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.