What is CVE-2021-35306?

CVE-2021-35306 is a medium-severity vulnerability in Axiosys Bento4, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2021-08-05.

How severe is CVE-2021-35306?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2021-35306 known to be exploited?

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

NULL pointer dereference in Axiosys Bento4

CVE-2021-35306

An issue was discovered in Bento4 through v1.6.0-636. A NULL pointer dereference exists in the function AP4_StszAtom::WriteFields located in Ap4StszAtom.cpp. It allows an attacker to cause a denial of service (DOS).

Published 2021-08-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (60.6th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 60.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Axiosys Bento4

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

Public proof-of-concept exploits

seviezhou/Kraken

References

github.com/axiomatic-systems/Bento4/issues/615 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-35306?: CVE-2021-35306 is a medium-severity vulnerability in Axiosys Bento4, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2021-08-05.
How severe is CVE-2021-35306?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2021-35306 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.