A heap use-after-free flaw was found in curl versions from 7.59.0 through 7.61.1 in the code related to closing an easy handle. When closing and cleaning up an 'easy' handle in the `Curl_close()` function, the library code first frees a struct (without nulling the pointer) and might then subsequently erroneously write to a struct field within that already freed struct.
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
| Link | Tags |
|---|---|
| https://security.gentoo.org/glsa/201903-03 | third party advisory vendor advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16840 | issue tracking third party advisory |
| https://github.com/curl/curl/commit/81d135d67155c5295b1033679c606165d4e28f3f | third party advisory patch |
| http://www.securitytracker.com/id/1042013 | vdb entry third party advisory |
| https://curl.haxx.se/docs/CVE-2018-16840.html | patch vendor advisory |
| https://usn.ubuntu.com/3805-1/ | third party advisory vendor advisory |