7.5

CVE-2025-40775: isc bind 9 Improper Handling of Undefined Values

CVSS: 7.5v3.1HighDeferred
AliasesALPINE-CVE-2025-40775UBUNTU-CVE-2025-40775USN-7526-1
Published 21-05-2025Last modified 23-05-2025
Open JSON

Vulnerability summary

CVE-2025-40775 is a high (CVSS 7.5) Improper Handling of Undefined Values vulnerability in isc bind 9. EPSS estimates a 15.30% chance of exploitation in the next 30 days, higher than 96.7% of scored vulnerabilities.

Overall risk
33/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
15.30%
0%100%
Medium · +0.08 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
SUSE-SU-2025:01787-1

Timeline

  1. 21-05-2025
    PublishedVulnerability first disclosed.
  2. 23-05-2025
    Last modifiedVulnerability information updated.

Description

When an incoming DNS protocol message includes a Transaction Signature (TSIG), BIND always checks it. If the TSIG contains an invalid value in the algorithm field, BIND immediately aborts with an assertion failure. This issue affects BIND 9 versions 9.20.0 through 9.20.8 and 9.21.0 through 9.21.7.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

15.30%

Chance of exploitation in the next 30 days

Percentile

97%

Versus all other CVEs

30-day change

+0.08 pp

From 15.22% on 18-09-2026

18-09-202618-10-2026
EPSS score
15.30%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Alpine1 product
  • bind< 9.18.37-r0 | < 9.20.9-r0
Debian1 product
  • bind9< 1:9.20.9-1
Isc1 product
  • bind 9≥ 9.20.0, ≤ 9.20.8 | ≥ 9.21.0, ≤ 9.21.7
Opensuse1 product
  • bind&distro=openSUSE Tumbleweed< 9.20.9-1.1
Ubuntu1 product
  • bind9< 1:9.20.4-3ubuntu1.1

5 vendors · 5 products

References

11 links
Show all 11 references