CVE-2018-16840

Advisory lineage Upstream: 0 Downstream: 9
Analyzed
Published: 31 Oct 2018, 18:00
Last modified:16 Apr 2026, 14:08

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.8 CRITICAL
v3.1 (nvd)
EPSS Score
0.29% LOW
0% probability +0.01%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

31 Oct 2018, 18:00
Published
Vulnerability first disclosed
16 Apr 2026, 14:08
Last Modified
Vulnerability information updated

Description

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.

CVSS Metrics

  • v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • v3.0•MEDIUM•Score: 4.3CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
  • v2.0•HIGH•Score: 7.5AV:N/AC:L/Au:N/C:P/I:P/A:P

EPSS Trends

Current EPSS score: 0.29%• Percentile: 53%

Techniques & Countermeasures

  • CWE-416•Use After Free

    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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected Systems

  • canonical•ubuntu_linux

    14.04 | 16.04 | 18.04 | 18.10

  • haxx•curl

    ≥ 7.59.0, < 7.62.0

  • the curl project•curl

    from 7.59.0 to 7.61.1

References (6)