CVE-2018-19791

Exp

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.

Published: 2018-12-03 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-19791 is rated High Exploit Risk (64.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.24%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2018-19791

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2018-19791

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.29% 1.24% +0.95%
2 2025-03-17 0.07% 0.29% +0.22%
3 2023-03-07 — 0.07% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-19791

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2018-19791

Affected software / configurations for CVE-2018-19791

Vendor Product Version Raw CPE
litespeedtech openlitespeed < 1.5.0 cpe:2.3:a:litespeedtech:openlitespeed:*:*:*:*:*:*:*:*
litespeedtech openlitespeed 1.5.0 cpe:2.3:a:litespeedtech:openlitespeed:1.5.0:-:*:*:*:*:*:*
litespeedtech openlitespeed 1.5.0 cpe:2.3:a:litespeedtech:openlitespeed:1.5.0:rc1:*:*:*:*:*:*
litespeedtech openlitespeed 1.5.0 cpe:2.3:a:litespeedtech:openlitespeed:1.5.0:rc2:*:*:*:*:*:*
litespeedtech openlitespeed 1.5.0 cpe:2.3:a:litespeedtech:openlitespeed:1.5.0:rc3:*:*:*:*:*:*
litespeedtech openlitespeed 1.5.0 cpe:2.3:a:litespeedtech:openlitespeed:1.5.0:rc4:*:*:*:*:*:*
litespeedtech openlitespeed 1.5.0 cpe:2.3:a:litespeedtech:openlitespeed:1.5.0:rc5:*:*:*:*:*:*

References for CVE-2018-19791

URL Tags
https://github.com/litespeedtech/openlitespeed/issues/117 Exploit Third Party Advisory
cvelogic Threat Intelligence