CVE-2018-16840
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.40%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 3.40% probability · 89th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- haxx/curl · canonical/ubuntu linux
- Source
- secalert@redhat.com
EPSS 3.4% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.securitytracker.com/id/1042013Third Party Advisory, VDB Entry
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16840Issue Tracking, Third Party Advisory
- https://curl.haxx.se/docs/CVE-2018-16840.htmlPatch, Vendor Advisory
- https://github.com/curl/curl/commit/81d135d67155c5295b1033679c606165d4e28f3fPatch, Third Party Advisory
- https://security.gentoo.org/glsa/201903-03Third Party Advisory
- https://usn.ubuntu.com/3805-1/Third Party Advisory
- http://www.securitytracker.com/id/1042013Third Party Advisory, VDB Entry
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16840Issue Tracking, Third Party Advisory
- https://curl.haxx.se/docs/CVE-2018-16840.htmlPatch, Vendor Advisory
- https://github.com/curl/curl/commit/81d135d67155c5295b1033679c606165d4e28f3fPatch, Third Party Advisory
- https://security.gentoo.org/glsa/201903-03Third Party Advisory
- https://usn.ubuntu.com/3805-1/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.