CVE-2021-30639

unknown
Published 2021-08-13 · Modified 2024-02-19
CVSS v3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v2
VIR risk

Description

A vulnerability in Apache Tomcat allows an attacker to remotely trigger a denial of service. An error introduced as part of a change to improve error handling during non-blocking I/O meant that the error flag associated with the Request object was not reset between requests. This meant that once a non-blocking I/O error occurred, all future requests handled by that request object would fail. Users were able to trigger non-blocking I/O errors, e.g. by dropping a connection, thereby creating the possibility of triggering a DoS. Applications that do not use non-blocking I/O are not exposed to this vulnerability. This issue affects Apache Tomcat 10.0.3 to 10.0.4; 9.0.44; 8.5.64.

Predictions

Exploit likelihood
30%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-30639

OS impact

OSVersionStatusFixed in
debian debianbookwormfixed0
debian debianbullseyefixed0
debian debianforkyfixed0
debian debiansidfixed0
debian debiantrixiefixed0

Package impact

EcosystemPackageVulnerableFixed
java Mavenorg.apache.tomcat:tomcat>=10.0.3,<10.0.510.0.5
java Mavenorg.apache.tomcat:tomcat>=9.0.0,<9.0.459.0.45
java Mavenorg.apache.tomcat:tomcat<8.5.658.5.65

References

Verify integrity in audit chain (admin only). AS-IS.