Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2021-25218

26
FAUCET Score

CVE-2021-25218 is a high-severity denial-of-service (DoS) vulnerability affecting specific versions of BIND 9 (9.16.19, 9.17.16, and 9.16.19-S1 of the Supported Preview Edition), including those in Fedora Project distributions. An unauthenticated attacker can remotely trigger a crash in the 'named' process by sending a specially crafted query, leading to service unavailability. While no public exploit code or active exploitation has been confirmed, the vulnerability has garnered some community discussion and media coverage, indicating awareness within the cybersecurity community.

Impacted Technologies

VendorProductVersion(s)CPE
9.16.19CPE matchmatch criteria
cpe:2.3:a:isc:bind:9.16.19:*:*:*:-:*:*:*
9.17.16CPE matchmatch criteria
cpe:2.3:a:isc:bind:9.17.16:*:*:*:-:*:*:*
9.17.16CPE matchmatch criteria
cpe:2.3:a:isc:bind:9.17.16:s1:*:*:supported_preview:*:*:*
34CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.59%
Probability of exploitation in next 30 days
EPSS Percentile
88.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0359 is in the 79th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2021-25218Important

bind: Too strict assertion check could be triggered when responses require UDP fragmentation if RRL is in use

Aug 18, 2021

References

kb.isc.org / v1/docs/cve-2021-25218
ExploitVendor Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/ZPJCLGSR4BTGFLBLGIE5TEQP2SNJKGVL
security.netapp.com / advisory/ntap-20210909-0002
Third Party Advisory
openwall.com / lists/oss-security/2021/08/18/3
Mailing ListPatchThird Party Advisory
openwall.com / lists/oss-security/2021/08/20/2
Mailing ListPatchThird Party Advisory