---
id: CVE-2026-19542
title: >-
  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 expl…
summary: >-
  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 expl…
severity: medium
cvss: 5.6
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-121
  - CWE-787
vendor: The GNU C Library
product: glibc
affected:
  - glibc >= 2.1 <= 2.44
patched:
  - hardened_images
published: '2026-09-14'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T18:17:47.257'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-19542'
references:
  - url: 'https://sourceware.org/bugzilla/show_bug.cgi?id=34506'
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: >-
      https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0018
    label: 3ff69d7a-14f2-4f67-a097-88dee7810d18
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-19542.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-19542'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2523249'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-19542'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-19542'
  - url: 'https://access.redhat.com/errata/RHSA-2026:59721'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00226
epssPercentile: 0.11856
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-14T19:41:54.952845Z'
scores:
  nvd: 5.6
  vendor: 4.2
ingestedAt: '2026-09-14T18:12:17.318Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:59721** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:59721)
- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-19542.json)