CVE-2025-40780: Cache poisoning due to weak PRNG

Published Oct 22, 2025
·
Updated

Cache poisoning due to weak PRNG

Other sources

In specific circumstances, due to a weakness in the Pseudo Random Number Generator (PRNG) that is used, it is possible for an attacker to predict the source port and query ID that BIND will use.

— Red Hat

Affected Software

9 affected componentsFixes available
ISC BIND 9>=9.16.0<=9.16.50, >=9.18.0<=9.18.39, >=9.20.0<=9.20.13, >=9.21.0<=9.21.12, >=9.16.8-S1<=9.16.50-S1, >=9.18.11-S1<=9.18.39-S1, >=9.20.9-S1<=9.20.13-S1
Microsoft azl3 bind 9.20.11-1
Microsoft cbl2 bind 9.16.50-2
Microsoft azl3 bind 9.20.15-1
Microsoft cbl2 bind 9.16.50-2
Patch available
F5 BIG-IP DNS=21.0.0
21.0.0.1
F5 BIG-IP DNS>=17.5.0<=17.5.1, =3, >=17.1.0<=17.1.3, =3
17.5.1.417.1.3.1
F5 BIG-IP DNS>=16.1.0<=16.1.6, =3
F5 BIG-IP DNS>=15.1.0<=15.1.10, =3

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 21.0.0.1
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 17.5.1.417.1.3.1
  3. Upgrade

    Upgrade ISC BIND 9 to a version that resolves this vulnerability.

    Fixed in 9.18.41
  4. Upgrade

    Upgrade ISC BIND 9 to a version that resolves this vulnerability.

    Fixed in 9.20.15
  5. Upgrade

    Upgrade ISC BIND 9 to a version that resolves this vulnerability.

    Fixed in 9.21.14
  6. Upgrade

    Upgrade ISC BIND 9 to a version that resolves this vulnerability.

    Fixed in 9.18.41-S1
  7. Upgrade

    Upgrade ISC BIND 9 to a version that resolves this vulnerability.

    Fixed in 9.20.15-S1

Event History

Oct 22, 2025
Data Sourced
via Red Hat·03:22 PM
DescriptionSeverityAffected Software
CVE Published
via MITRE·03:48 PM
Data Sourced
via MITRE·03:48 PM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·04:15 PM
DescriptionSeverityWeakness
Oct 25, 2025
Data Sourced
via Microsoft·01:01 AM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·01:01 AM
Affected Software
Updated
via Microsoft·01:01 AM
DescriptionSeverity
Nov 24, 2025
Advisory Published
via F5·04:43 PM
Data Sourced
via F5·04:43 PM
DescriptionSeverityWeaknessAffected Software
Free Weekly Intel

Don't miss critical vulnerabilities

Join thousands of security professionals who receive our weekly digest of trending CVEs, zero-days, and exploited vulnerabilities.

No spam. Unsubscribe anytime.

Frequently Asked Questions

1

What is the severity of CVE-2025-40780?

CVE-2025-40780 has been assigned a medium severity rating due to its potential for predictable source port and query ID exploitation.

2

How do I fix CVE-2025-40780?

To fix CVE-2025-40780, upgrade to BIND 9 versions 9.16.51 or later, 9.18.40 or later, or 9.20.14 or later.

3

Which versions of BIND are affected by CVE-2025-40780?

BIND versions 9.16.0 through 9.16.50, 9.18.0 through 9.18.39, 9.20.0 through 9.20.13, and 9.21.0 through 9.21.12 are affected.

4

What types of attacks could exploit CVE-2025-40780?

CVE-2025-40780 could be exploited in DNS cache poisoning attacks where an attacker predicts port and query ID values.

5

Is CVE-2025-40780 fixed in the latest BIND versions?

Yes, the latest BIND versions post the specified vulnerable ranges include fixes for CVE-2025-40780.

Company

Resources

Contact

SecAlerts Pty Ltd.
132 Wickham Terrace
Fortitude Valley,
QLD 4006, Australia
info@secalerts.co
By using SecAlerts services, you agree to our services end-user license agreement. This website is safeguarded by reCAPTCHA and governed by the Google Privacy Policy and Terms of Service. All names, logos, and brands of products are owned by their respective owners, and any usage of these names, logos, and brands for identification purposes only does not imply endorsement. If you possess any content that requires removal, please get in touch with us.
© 2026 SecAlerts Pty Ltd.
ABN: 70 645 966 203, ACN: 645 966 203