CVE-2019-20800: In Cherokee through 1.2.104, remote attackers can trigger an out-of-bounds write in cherokee_handler_cgi_add_e

Q: How do I fix CVE-2019-20800?

cherokee: upgrade to newer than 1.2.104. Exact commands for each OS are on this page.

Q: Is CVE-2019-20800 being exploited?

CVE-2019-20800 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2019-20800 affect?

CVE-2019-20800 affects cherokee. Severity is critical (CVSS 9.8). In Cherokee through 1.2.104, remote attackers can trigger an out-of-bounds write in cherokee_handler_cgi_add_env_pair in handler_cgi.c by sending many request headers, as demonstrated by a GET request with many "Host: 127.0.0.1" headers.

Q: How urgent is CVE-2019-20800?

Priority 65/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2019-20800 is a critical-severity flaw (CVSS 9.8) affecting cherokee. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Cherokee through 1.2.104, remote attackers can trigger an out-of-bounds write in cherokee_handler_cgi_add_env_pair in handler_cgi.c by sending many request headers, as demonstrated by a GET request with many "Host: 127.0.0.1" headers.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.1% (top 18%)
CISA exploited list	No
Weakness	CWE-787
Published	2020-05-18
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: cherokee-project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-05-18 00:15 UTCPublished CVE record published
2026-06-17 02:31 UTCUpdated Record last modified

cherokee-project cherokee UPGRADE

Affected: <= 1.2.104

Fixed in: newer than 1.2.104

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy cherokee || rpm -q cherokee || cherokee --version

2. UPGRADE to newer than 1.2.104 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cherokee

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cherokee

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2019-20800?

cherokee: upgrade to newer than 1.2.104. Exact commands for each OS are on this page.

Is CVE-2019-20800 being exploited?

CVE-2019-20800 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2019-20800 affect?

CVE-2019-20800 affects cherokee. Severity is critical (CVSS 9.8). In Cherokee through 1.2.104, remote attackers can trigger an out-of-bounds write in cherokee_handler_cgi_add_env_pair in handler_cgi.c by sending many request headers, as demonstrated by a GET request with many "Host: 127.0.0.1" headers.

How urgent is CVE-2019-20800?

Priority 65/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2020-12845 HIGH 7.5 UPGRADE Cherokee 0.4.27 to 1.2.104 is affected by a denial of service due to a NULL pointer dereferences
CVE-2019-20799 HIGH 7.5 UPGRADE In Cherokee through 1.2.104, multiple memory corruption errors may be used by a remote attacker to destabilize
CVE-2019-20798 HIGH 8.4 UPGRADE An XSS issue was discovered in handler_server_info.c in Cherokee through 1.2.104

References

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