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Fencer Vulns
medium 5.9

CVE-2026-27853 json

Out-of-bounds write when rewriting large DNS packets

published 2026-03-31 7 mo ago modified 2026-07-25 3 mo ago also EUVD-2026-17407

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

An attacker might be able to trigger an out-of-bounds write by sending crafted DNS responses to a DNSdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code. In some cases the rewritten packet might become larger than the initial response and even exceed 65535 bytes, potentially leading to a crash resulting in denial of service.

Patch / fix

  • PowerDNS DNSdist 1.9.12, 2.0.3
  • dnsdist Debian 13 1.9.14-0+deb13u1
  • dnsdist Debian 14 2.0.3-1

debian advisories DEBIAN-CVE-2026-27853

  • dnsdist SLES for SAP applications 16.0, SLES 16.0 1.9.13-160000.1.1
  • dnsdist SLE Module for Basesystem 15 SP7 1.9.12-150700.3.9.1

suse advisories SUSE-SU-2026:22319-1SUSE-SU-2026:1618-1

  • dnsdist openSUSE Leap 16.0 1.9.13-160000.1.1

opensuse advisories openSUSE-SU-2026:21015-1

  • dnsdist Alpine 3.24, Alpine 3.23 2.0.4-r0

alpine advisories ALPINE-CVE-2026-27853

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2026-27853 updated cvss 5.9

dnsdist: dnsdist: Denial of Service via crafted DNS responses

  • 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • PowerDNS DNSdist

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.