CVE-2026-82717
Publication date 16 September 2026
Last updated 6 October 2026
Ubuntu priority
Description
In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in that can progressively corrupt heap memory and under certain systems and compilation options could lead to remote code execution. The vulnerability starts when CNAME synthesis during an upstream response needs to enforce(rewrite) a max TTL value in the packet buffer. Coupled with a compression pointer that points to the overwritten value and invalidates the domain name, it leads to an error path that does not properly move the buffer position and allows for the heap buffer overflow. Since this is heavily reliant on heap memory layout, results are memory corruption that eventually leads to a crash and under specific systems and compilation options remote code execution.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| unbound | 26.04 LTS resolute |
Fixed 1.24.2-1ubuntu2.3
|
| 24.04 LTS noble |
Fixed 1.19.2-1ubuntu3.10
|
|
| 22.04 LTS jammy |
Fixed 1.13.1-1ubuntu5.16
|
|
| 20.04 LTS focal |
Fixed 1.9.4-2ubuntu1.11+esm2
|
|
| 18.04 LTS bionic |
Fixed 1.6.7-1ubuntu2.6+esm5
|
|
| 16.04 LTS xenial |
Fixed 1.5.8-1ubuntu1.1+esm4
|
|
| 14.04 LTS trusty |
Fixed 1.4.22-1ubuntu4.14.04.3+esm4
|
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| Package | Patch details |
|---|---|
| unbound |
Severity score breakdown
CVSS version:
Base score
8.4 · High
Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U
Base score
9.8 · Critical
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
Related Ubuntu Security Notices (USN)
- USN-8873-1
- Unbound vulnerabilities
- 6 October 2026