CVE-2026-100290
Received
Received - Intake
Double Free and Use-After-Free in GNU C Library
Vulnerability report for CVE-2026-100290, 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
The regcomp and regexec functions in the GNU C Library version 2.3 to version 2.44 may read freed memory and free the same heap block twice when a memory allocation fails while a regular expression is compiled or matched. The re_dfa_add_node (the NFA node table) and build_range_exp (bracket ranges) grow several arrays with consecutive realloc calls and store the new pointers only after all of them succeed. When a later call fails, the pattern buffer keeps pointers to blocks that were already freed, and the error cleanup frees them again. In regexec, the back-reference cache (match_ctx_add_entry) frees its array when a realloc fails but keeps the pointer, which is freed again on the error path.
An attacker does not need to supply a crafted regular expression: patterns large enough to grow these arrays are common. The failure has to hit a specific allocation, though, so the issue can only be reached when the system is already under memory pressure. An attacker who supplies the pattern or the subject string has little control over which allocation fails, so the expected impact is a crash of the process. This issue affects all architectures and ABIs supported by the GNU C Library.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| The GNU C Library | glibc | From 2.3 (inc) to 2.44 (inc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-415 | The product calls free() twice on the same memory address. |
