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Fencer Vulns
critical 9.8

CVE-2021-33833 json

ConnMan (aka Connection Manager) 1.30 through 1.39 has a stack-based buffer overflow in uncompress in dnsproxy.c via NAME, RDATA, or RDLENG…

published 2021-06-09 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20507

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.6%
EPSS 2.6% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

ConnMan (aka Connection Manager) 1.30 through 1.39 has a stack-based buffer overflow in uncompress in dnsproxy.c via NAME, RDATA, or RDLENGTH (for A or AAAA).

Patch / fix

  • connman Debian 14, Debian 13, Debian 12 1.36-2.2

debian advisories DEBIAN-CVE-2021-33833

  • connman Ubuntu 20.04 LTS 1.36-2ubuntu0.1
  • connman Ubuntu Pro 18.04 LTS 1.35-6ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-33833

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

  • connman openSUSE Tumbleweed 1.40-2.2

opensuse advisories openSUSE-SU-2024:10692-1

  • connman Arch Linux 1.40-1

arch linux advisories AVG-2055

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-2021-33833 updated cvss 8.1

connman: stack based buffer overflow in uncompress in dnsproxy.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

2.57% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com http://www.openwall.com/lists/oss-security/2022/01/25/1 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.