CVE-2026-19542
Publication date 27 August 2026
Last updated 16 September 2026
Ubuntu priority
Description
Calling tdelete on a sufficiently deep tree in the GNU C Library version 2.1 to 2.44 may write one pointer past the end of an alloca-allocated array on the stack, which may crash the application. The tdelete implementation keeps an explicit stack of parent nodes for rebalancing, which is grown as needed while descending the tree. Two rebalancing branches push an additional entry without checking the capacity, and write past the array when the stack is exactly full. Triggering this requires a node at a depth of exactly 40 (or 40 plus a multiple of 20), which implies a tree with at least a million nodes, so an attacker must drive a large number of insertions and deletions through an application that uses tsearch and tdelete. The written value is a pointer into a tree node and is not directly attacker controlled. No affected application in common distributions has been identified.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| glibc | 26.04 LTS resolute |
Fixed 2.43-2ubuntu2.4
|
| 24.04 LTS noble |
Fixed 2.39-0ubuntu8.9
|
|
| 22.04 LTS jammy |
Fixed 2.35-0ubuntu3.15
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
|
| eglibc | 26.04 LTS resolute | Not in release |
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 14.04 LTS trusty |
Needs evaluation
|
Patch details
| Package | Patch details |
|---|---|
| glibc |
Severity score breakdown
CVSS version: CVSS v3.0
Base score
5.6 · Medium
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
References
Related Ubuntu Security Notices (USN)
- USN-8737-1
- GNU C Library vulnerabilities
- 8 September 2026
- USN-8737-2
- GNU C Library vulnerabilities
- 10 September 2026