CVE-2020-15689: Appweb before 7.2.2 and 8.x before 8.1.0, when built with CGI support, mishandles an HTTP request with a Range

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HIGH 7.5REMOTEUPGRADE

CVE-2020-15689 is a high-severity flaw (CVSS 7.5) affecting appweb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Appweb before 7.2.2 and 8.x before 8.1.0, when built with CGI support, mishandles an HTTP request with a Range header that lacks an exact range. This may result in a NULL pointer dereference and cause a denial of service.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-476
Published	2020-07-13
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: embedthis

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

Am I affected?

Timeline

2020-07-13 14:15 UTCPublished CVE record published
2026-06-17 02:57 UTCUpdated Record last modified

embedthis appweb UPGRADE

Affected: < 7.2.2 · >= 8.0.0 and < 8.1.0

Fixed in: 7.2.2, 8.1.0

Safe to downgrade to: a release before 8.0.0

1. Check installed version

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

2. UPGRADE to 7.2.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade appweb

Note

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

3. If no update is available yet, DOWNGRADE to a release before 8.0.0 (Debian / Ubuntu)

apt-cache madison appweb sudo apt install appweb=<VERSION_BEFORE_8.0.0> sudo apt-mark hold appweb

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list appweb sudo dnf downgrade appweb-<VERSION_BEFORE_8.0.0> sudo dnf versionlock add appweb

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2020-15689?

appweb: upgrade to 7.2.2, 8.1.0. Exact commands for each OS are on this page.

Is CVE-2020-15689 being exploited?

CVE-2020-15689 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-2020-15689 affect?

CVE-2020-15689 affects appweb. Severity is high (CVSS 7.5). Appweb before 7.2.2 and 8.x before 8.1.0, when built with CGI support, mishandles an HTTP request with a Range header that lacks an exact range. This may result in a NULL pointer dereference and cause a denial of service.

How urgent is CVE-2020-15689?

Priority 49/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-33254 HIGH 7.5 DOWNGRADE An issue was discovered in src/http/httpLib.c in EmbedThis Appweb Community Edition 8.2.1, allows attackers to

References

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