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Vulnerability record · CVE-2021-33254 · published 2 June 2022

CVE-2021-33254: Embedthis appweb null pointer dereference vulnerability

Embedthis · Appweb

An issue was discovered in src/http/httpLib.c in EmbedThis Appweb Community Edition 8.2.1, allows attackers to cause a denial of service via the stream paramter to the parseUri function.

7.5 CVSS 3.1 High EPSS 1.5% · top 26.4% CWE-476 · NULL pointer dereference
7.5CVSS 3.1 base score, v2 5.0
1.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

An issue was discovered in src/http/httpLib.c in EmbedThis Appweb Community Edition 8.2.1, allows attackers to cause a denial of service via the stream paramter to the parseUri function.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://awxylitol.github.io/2021/05/09/embedthis-appweb-npd-bug.html ExploitPatchThird Party Advisory
https://awxylitol.github.io/2021/05/09/embedthis-appweb-npd-bug.html ExploitPatchThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.1CVE-2018-8715Embedthis appweb improper authentication vulnerabilityThe Embedthis HTTP library, and Appweb versions before 7.0.3, have a logic flaw related to the authCondition function in http/httpLib.c. With a forge…EPSS 23%7.5CVE-2020-15689Embedthis appweb null pointer dereference vulnerabilityAppweb 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…EPSS 1.3%7.5CVE-2018-15504Embedthis appweb null pointer dereference vulnerabilityAn issue was discovered in Embedthis GoAhead before 4.0.1 and Appweb before 7.0.2. The server mishandles some HTTP request fields associated with tim…EPSS 2.8%7.5CVE-2018-15505Embedthis appweb null pointer dereference vulnerabilityAn issue was discovered in Embedthis GoAhead before 4.0.1 and Appweb before 7.0.2. An HTTP POST request with a specially crafted "Host" header field …EPSS 2.2%5.0CVE-2014-9708Embedthis Appweb NULL pointer dereference via empty Range headerEmbedthis Appweb before 4.6.6 and 5.x before 5.2.1 dereferences a NULL pointer when it receives a Range header with an empty value, such as "Range: x…EPSS 56%analysed6.2CVE-2026-21525Windows Remote Access Connection Manager null pointer dereference DoSWindows Remote Access Connection Manager contains a null pointer dereference (CWE-476) that lets an unauthorized attacker deny service locally. The f…KEVEPSS 4.8%analysed

Source: NIST National Vulnerability Database (record CVE-2021-33254), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.