CVEvulnerability

CVE-2026-5947

5.9 MEDIUM Published 2026-05-20 Modified 2026-08-24 Official page ↗
Status
Modified
Published
2026-05-20
Last modified
2026-08-24
Assigner
[email protected]
CVSS 3.1 ([email protected])
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1 ([email protected])
5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)
7.5 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
CWE-362, CWE-367, CWE-416

Description

Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursive-clients" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.28 through 9.18.49 and 9.18.28-S1 through 9.18.49-S1 are NOT affected.

Affected configurations

• isc bind (>= 9.20.0 < 9.20.23) • isc bind (>= 9.21.0 < 9.21.22)

Related

Weakness · CWE (3)

  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization weakness
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition weakness
  • CWE-416 Use After Free weakness

References