CVE-2018-21018
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
- Record
CVE-2018-21018- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-613
- Updated
- 2026-11-02
CVE List No score
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
- Record
CVE-2018-21018- Updated
- 2026-11-02
EUVDEUVD-2018-13542 No score
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
- Record
EUVD-2018-13542- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4gqg-m5mw-g8mg
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
- Record
GHSA-4gqg-m5mw-g8mg- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-613
- Updated
- 2026-11-02
OSV
Mastodon before 2.6.3 mishandles timeouts of incompletely established sessions.
- Record
CVE-2018-21018- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2018-21018 is a critical vulnerability (CVSS 9.8) in Joinmastodon Mastodon, published September 22, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.56%, the 85th percentile. No source names a fixed version.