What is CVE-2021-3881?

CVE-2021-3881 is a critical-severity vulnerability in Bfabiszewski Bfabiszewski/libmobi, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2021-10-15.

How severe is CVE-2021-3881?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Out-of-bounds Read in Bfabiszewski Bfabiszewski/libmobi

CVE-2021-3881

libmobi is vulnerable to Out-of-bounds Read

Vulnerability class: Buffer Overflow

Published 2021-10-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.012 (65.8th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 65.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Bfabiszewski Bfabiszewski/libmobi — versions unspecified
Libmobi Project

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

huntr.dev/bounties/540fd115-7de4-4e19-a918-5ee61f5157c1 (Exploit, Third Party Advisory)
github.com/bfabiszewski/libmobi/commit/bec783e6212439a335ba6e8df7ab8ed610ca9a21 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-3881?: CVE-2021-3881 is a critical-severity vulnerability in Bfabiszewski Bfabiszewski/libmobi, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2021-10-15.
How severe is CVE-2021-3881?: Critical severity. CVSS v3 base score is 9.8 out of 10.