CVE-2026-115819
Received
Received - Intake
Heap-based Buffer Overflow in GNU C Library scanf Functions
Vulnerability report for CVE-2026-115819, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-11-11
Last updated on: 2026-11-11
Assigner: GNU C Library
Description
Description
Calling the wide scanf family of functions (swscanf, fwscanf, wscanf, vswscanf, vfwscanf and vwscanf) with a %s or %[ conversion without the 'l' length modifier in the GNU C Library version 2.2 to version 2.44 writes an extra null byte one past the end of the destination array when the converted multibyte string and its terminating null byte exactly fill that array.
These conversions store each wide input character into the caller's char array as a multibyte sequence. The conversion ends with the sequence that returns to the initial shift state, which also stores the terminating null byte, and the functions then append a second null byte. A destination sized for the converted string and one terminator, as the C standard requires the caller to provide, is therefore written one byte past its end. The out-of-bounds byte is always a null byte, which may corrupt adjacent data or crash the process. An attacker who supplies the input can trigger the overflow with a string whose converted length exactly fills the destination.
The narrow scanf functions, the %ls and %l[ conversions into a wchar_t array, and the 'a' and 'm' allocation modifiers are not affected, and storing a wide scanf conversion into a narrow char array is uncommon. This issue affects all architectures and ABIs supported by the GNU C Library.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| The GNU C Library | glibc | From 2.2 (inc) to 2.44 (inc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-193 | A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value. |
