What is CVE-2021-33254?

CVE-2021-33254 is a high-severity vulnerability in Embedthis Appweb, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2022-06-02.

How severe is CVE-2021-33254?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2021-33254 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

NULL pointer dereference in Embedthis Appweb

CVE-2021-33254

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.

Published 2022-06-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.015 (75.0th percentile), scored 2026-11-01.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 75.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.015 · newest: 0.015 · change: +0.000

Affected products

Embedthis Appweb — versions 8.2.1
Linux Kernel

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

Public proof-of-concept exploits

References

awxylitol.github.io/2021/05/09/embedthis-appweb-npd-bug.html (Exploit, Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-33254?: CVE-2021-33254 is a high-severity vulnerability in Embedthis Appweb, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2022-06-02.
How severe is CVE-2021-33254?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-33254 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.