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CVE-2019-25033

29
FAUCET Score

CVE-2019-25033 describes an integer overflow vulnerability in the regional allocator of Unbound versions prior to 1.9.5, affecting Debian and NLnetlabs Unbound products. This vulnerability carries a critical CVSS score of 9.8, indicating a network-exploitable flaw with low attack complexity that could lead to high impact on confidentiality, integrity, and availability. Despite the high severity, the vendor disputes its exploitability in a running Unbound installation, and there is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.9.5CPE matchmatch criteria
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.78%
Probability of exploitation in next 30 days
EPSS Percentile
76.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0178 is in the 64th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: unbound-0:1.16.2-2.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Extended Update SupportFixed in: unbound-0:1.7.3-17.el8_6.1
View patch

Vendor Advisories (1)

redhatCVE-2019-25033Moderate

unbound: integer overflow in the regional allocator via the ALIGN_UP macro

Dec 11, 2019

References

lists.debian.org / debian-lts-announce/2021/05/msg00007.html
Mailing ListThird Party Advisory
ostif.org / our-audit-of-unbound-dns-by-x41-d-sec-full-results
Not ApplicableThird Party Advisory
security.netapp.com / advisory/ntap-20210507-0007
Third Party Advisory