What is CVE-2021-39522?

CVE-2021-39522 is a high-severity vulnerability in GNU Libredwg, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2021-09-20.

How severe is CVE-2021-39522?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2021-39522 known to be exploited?

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

Buffer overflow in GNU Libredwg

CVE-2021-39522

An issue was discovered in libredwg through v0.10.1.3751. bit_wcs2len() in bits.c has a heap-based buffer overflow.

Vulnerability class: Buffer Overflow

Published 2021-09-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.011 (64.9th percentile), scored 2026-10-30.

Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 64.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

GNU Libredwg

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

Public proof-of-concept exploits

seviezhou/Kraken

References

github.com/LibreDWG/libredwg/issues/255 (Exploit, Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-39522?: CVE-2021-39522 is a high-severity vulnerability in GNU Libredwg, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2021-09-20.
How severe is CVE-2021-39522?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2021-39522 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.