CVE-2026-3805
Use-After-Free Vulnerability in curl SMB Requests Causes Memory Corruption
Publication date: 2026-03-11
Last updated on: 2026-03-12
Assigner: curl
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| haxx | curl | From 8.13.0 (inc) to 8.19.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-3805 is a use-after-free vulnerability in curl that occurs during SMB connection reuse. Specifically, when curl makes a second SMB request to the same host, it incorrectly uses a data pointer that points to memory that has already been freed.
This causes curl to perform a strlen() operation on this freed memory pointer and then check if the string length is less than or equal to 1024 before copying the string into the outgoing package.
Because the memory has been freed, it may have been overwritten by other application data, potentially leading to leakage of sensitive information.
The vulnerability affects curl versions 8.13.0 through 8.18.0 and was fixed in version 8.19.0.
How can this vulnerability impact me? :
This vulnerability can potentially lead to leakage of sensitive data if the freed memory was overwritten by application data since the previous transfer.
However, exploitation is considered extremely difficult because it is unlikely that applications would execute the exact sequence of operations without crashing or encountering other issues.
Therefore, the overall risk posed by this vulnerability is minimal.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
There are no specific detection commands or network/system detection methods provided for this vulnerability in the available resources.
What immediate steps should I take to mitigate this vulnerability?
To mitigate the CVE-2026-3805 vulnerability, it is recommended to upgrade curl and libcurl to version 8.19.0 or later, where the issue has been fixed.
Alternatively, apply the patch provided for this vulnerability and rebuild libcurl.
If upgrading or patching is not immediately possible, avoid using SMB transfers with curl to prevent triggering the vulnerability.