What is CVE-2021-28855?

CVE-2021-28855 is a medium-severity vulnerability in Entropymine Deark, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2021-04-14.

How severe is CVE-2021-28855?

Medium severity. CVSS v3 base score is 5.5 out of 10.

NULL pointer dereference in Entropymine Deark

CVE-2021-28855

In Deark before 1.5.8, a specially crafted input file can cause a NULL pointer dereference in the dbuf_write function (src/deark-dbuf.c).

Published 2021-04-14 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.009 (58.0th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Entropymine Deark

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

fatihhcelik.github.io/posts/NULL-Pointer-Dereference-Deark/ (Patch, Third Party Advisory)
github.com/jsummers/deark/commit/287f5ac31dfdc074669182f51ece637706070eeb (Patch, Third Party Advisory)
github.com/fuzzing2026/CVE-PoCs/tree/main/deark-CVE-2021-28855

Frequently asked questions

What is CVE-2021-28855?: CVE-2021-28855 is a medium-severity vulnerability in Entropymine Deark, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2021-04-14.
How severe is CVE-2021-28855?: Medium severity. CVSS v3 base score is 5.5 out of 10.