CVE-2020-11709

cpp-httplib through 0.5.8 does not filter \r\n in parameters passed into the set_redirect and...

7.5 High

cpp-httplib through 0.5.8 does not filter \r\n in parameters passed into the set_redirect and set_header functions, which creates possibilities for CRLF injection and HTTP response splitting in some specific contexts.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: None

Exploit likelihood

1.68%Up 1.1 points since Apr 14, 2021

What each source reports

NVD Score used 7.5

Record: CVE-2020-11709
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0: 5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness: CWE-74
Updated: 2026-11-02

CVE List No score

Record: CVE-2020-11709
Updated: 2026-11-02

EUVDEUVD-2020-4051 No score

Record: EUVD-2020-4051
Updated: 2026-11-03

GitHub AdvisoriesGHSA-fxvr-q2f8-9vxv 7.5

cpp-httplib through 0.5.8 does not filter \r\n in parameters passed into the set_redirect and...

Record: GHSA-fxvr-q2f8-9vxv
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness: CWE-74
Updated: 2026-11-02

OSV 7.5

Record: CVE-2020-11709
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2020-11709 7.5

Record: UBUNTU-CVE-2020-11709
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated: 2026-11-02

Affected products

yhirose cpp-httplib

Affected packages

Affected packages
Package	Affected	Fixed
`qtwebengine-opensource-src` Ubuntu:Pro:18.04:LTS	All versions, plus listed versions 5.9.1+dfsg-45.9.1+dfsg-4ubuntu15.9.2+dfsg-2ubuntu15.9.3+dfsg-0ubuntu15.9.4+dfsg-0ubuntu15.9.5+dfsg-0ubuntu25.9.5+dfsg-0ubuntu2+esm1	None known
`qtwebengine-opensource-src` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 5.12.4+dfsg-1ubuntu15.12.4+dfsg-1ubuntu35.12.5+dfsg-3ubuntu15.12.5+dfsg-6ubuntu25.12.5+dfsg-7 Show 4 moreShow less 5.12.5+dfsg-7build15.12.8+dfsg-0ubuntu15.12.8+dfsg-0ubuntu1.15.12.8+dfsg-0ubuntu1.1+esm1	None known
`qtwebengine-opensource-src` Ubuntu:Pro:22.04:LTS	All versions, plus listed versions 5.15.6+dfsg-15.15.6+dfsg-25.15.7+dfsg-25.15.8+dfsg-15.15.8+dfsg-1build1 Show 4 moreShow less 5.15.8+dfsg-1build25.15.8+dfsg-25.15.9+dfsg-15.15.9+dfsg-1ubuntu0.1~esm1	None known
`qtwebengine-opensource-src` Ubuntu:Pro:24.04:LTS	All versions, plus listed versions 5.15.15+dfsg-25.15.15+dfsg-2build25.15.15+dfsg-2ubuntu15.15.16+dfsg-15.15.16+dfsg-1ubuntu25.15.16+dfsg-1ubuntu45.15.16+dfsg-35.15.16+dfsg-3ubuntu0.1~esm1	None known
`qtwebengine-opensource-src` Ubuntu:25.10	All versions, plus listed versions 5.15.18+dfsg-25.15.18+dfsg-2build15.15.19+dfsg-15.15.19+dfsg2-1	None known
`qtwebengine-opensource-src` Ubuntu:26.10	All versions, plus listed versions 5.15.19+dfsg2-45.15.19+dfsg2-65.15.19+dfsg2-7	None known
`qtwebengine-opensource-src` Ubuntu:Pro:26.04:LTS	All versions, plus listed versions 5.15.19+dfsg2-15.15.19+dfsg2-1build15.15.19+dfsg2-25.15.19+dfsg2-35.15.19+dfsg2-45.15.19+dfsg2-4ubuntu0.1~esm1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-11709 is a high vulnerability (CVSS 7.5) in Yhirose Cpp-httplib, published April 12, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.68%, the 77th percentile. No source names a fixed version.