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.

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Vendors Products
Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-8737-1 GNU C Library vulnerabilities
Ubuntu USN Ubuntu USN USN-8737-2 GNU C Library vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Mon, 14 Sep 2026 21:00:00 +0000

Type Values Removed Values Added
Description A flaw was found in glibc. An out-of-bounds array write vulnerability exists within the `tdelete` function. This issue occurs due to incorrect management of array sizes, which can lead to memory corruption. A local attacker with low privileges could potentially exploit this to cause a denial of service or disclose sensitive information. 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.
Title glibc: Fix out-of-bounds array write in tdelete Stack-based out-of-bounds write in tdelete during tree rebalancing
Weaknesses CWE-121
References
Metrics cvssV3_1

{'score': 4.2, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

cvssV3_1

{'score': 5.6, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'}


Mon, 31 Aug 2026 21:45:00 +0000

Type Values Removed Values Added
First Time appeared Gnu
Gnu glibc
Vendors & Products Gnu
Gnu glibc

Tue, 25 Aug 2026 12:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in glibc. An out-of-bounds array write vulnerability exists within the `tdelete` function. This issue occurs due to incorrect management of array sizes, which can lead to memory corruption. A local attacker with low privileges could potentially exploit this to cause a denial of service or disclose sensitive information.
Title glibc: Fix out-of-bounds array write in tdelete
Weaknesses CWE-787
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.2, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:L'}

threat_severity

Moderate


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: glibc

Published:

Updated: 2026-09-14T19:42:06.277Z

Reserved: 2026-08-11T13:00:37.679Z

Link: CVE-2026-19542

cve-icon Vulnrichment

Updated: 2026-09-14T19:42:00.447Z

cve-icon NVD

Status : Received

Published: 2026-09-14T18:17:46.850

Modified: 2026-09-14T20:16:43.363

Link: CVE-2026-19542

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-25T06:49:13Z

Links: CVE-2026-19542 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-15T13:00:17Z

Weaknesses