CVE-2021-30639

NameCVE-2021-30639
DescriptionA 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
tomcat8 (PTS)stretch8.5.54-0+deb9u1fixed
stretch (security)8.5.54-0+deb9u8fixed
tomcat9 (PTS)buster9.0.31-1~deb10u5fixed
buster (security)9.0.31-1~deb10u6fixed
bullseye9.0.43-2~deb11u1fixed
bullseye (security)9.0.43-2~deb11u2fixed
bookworm, sid9.0.53-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
tomcat8sourcestretch(not affected)
tomcat8source(unstable)(unfixed)
tomcat9source(unstable)(not affected)

Notes

- tomcat9 <not-affected> (Vulnerable code introduced later in 9.0.44)
[stretch] - tomcat8 <not-affected> (Vulnerable code was introduced later)
https://bz.apache.org/bugzilla/show_bug.cgi?id=65203
https://github.com/apache/tomcat/commit/8ece47c4a9fb9349e8862c84358a4dd23c643a24 (9.0.45)
https://github.com/apache/tomcat/commit/411caf29ac1c16e6ac291b6e5543b2371dbd25e2 (8.5.65)

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