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Fencer Vulns
critical 9.8

CVE-2021-44847 json

A stack-based buffer overflow in handle_request function in DHT.c in toxcore 0.1.9 through 0.1.11 and 0.2.0 through 0.2.12 (caused by an im…

published 2021-12-13 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-31650

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.1%
EPSS 4.1% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

A stack-based buffer overflow in handle_request function in DHT.c in toxcore 0.1.9 through 0.1.11 and 0.2.0 through 0.2.12 (caused by an improper length calculation during the handling of received network packets) allows remote attackers to crash the process or potentially execute arbitrary code via a network packet.

Patch / fix

  • libtoxcore Debian 14, Debian 13, Debian 12 0.2.13-1

debian advisories DEBIAN-CVE-2021-44847

  • libtoxcore Ubuntu 22.04 LTS 0.2.13-1

ubuntu advisories UBUNTU-CVE-2021-44847

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • qtox openSUSE Tumbleweed 1.17.4-1.1
  • c-toxcore Package Hub 15 SP3, Package Hub 15 SP2, Package Hub 15 SP1 +2 more 0.2.13-bp153.2.3.1

opensuse advisories openSUSE-SU-2024:11846-1openSUSE-SU-2021:1640-1

  • toxcore Arch Linux 1:0.2.13-1

arch linux advisories AVG-2627

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-44847 updated cvss 8.1

toxcore: stack-based buffer overflow in handle_request() in DHT.c

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.13% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/TokTok/c-toxcore/pull/1718 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.