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CVE-2021-37311

24
FAUCET Score

CVE-2021-37311 is a buffer overflow vulnerability in fcitx5 version 5.0.8, allowing unauthenticated attackers to trigger a denial of service by sending a specially crafted message to the application's listening port. With a CVSS score of 7.5 (HIGH), this vulnerability is easily exploitable over the network with low attack complexity, leading to a complete loss of availability. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
5.0.8CPE matchmatch criteria
cpe:2.3:a:fcitx_5_project:fcitx_5:5.0.8:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.93%
Probability of exploitation in next 30 days
EPSS Percentile
56.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0093 is in the 32nd percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

fcitx-im.org
Product
github.com / fcitx/fcitx5/pull/308
ExploitPatchThird Party Advisory