CVE-2026-19542

MEDIUM
Published Sep 14, 2026 Modified Sep 14, 2026 CWE-121

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.

Is your site exposed to CVE-2026-19542?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.6
MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

EPSS — Exploit Prediction

0.0028
Probability of exploitation
0.20%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-121 CWE-121

References

Frequently Asked Questions

What is CVE-2026-19542? +
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. It has a CVSS v3.1 base score of 5.6 (MEDIUM).
How severe is CVE-2026-19542? +
CVE-2026-19542 has a CVSS v3.1 score of 5.6 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-19542? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-6239

A stack‑based buffer overflow vulnerability exists in Tapo C520WS v2 in the ONVIF CreateUsers service, where the device fails to …
CVE-2026-57161

PJSIP is a free and open source multimedia communication library written in C. Prior to commit acc03b5, a stack buffer …
CVE-2026-8356

LibreOffice can import presentations in the legacy binary PPT format. A stack buffer overflow existed when importing a colour-replacement record. …
CVE-2026-40489

editorconfig-core-c is an EditorConfig core library for use by plugins supporting EditorConfig parsing. Versions up to and including 0.12.10 have …
CVE-2025-26382

Under certain circumstances the iSTAR Configuration Utility (ICU) tool could have a buffer overflow issue
CVE-2025-1533

A stack buffer overflow has been identified in the AsIO3.sys driver. This vulnerability can be triggered by input manipulation, may …

Don't wait for an exploit

Scan your website for vulnerabilities like CVE-2026-19542 — free, no signup required.