High, CVSS 7.5MavenPublished
Unbounded connection acceptance leads to file handle exhaustion
CVE-2021-21293 · GHSA-xmw9-q7x9-j5qc
- Affected
- Maven org.http4s:blaze-core_2.12 < 0.14.15
- Fixed in
- 0.14.15· Vendor fix available
- Issue
- Impact All servers running blaze-core <= 0.14.14, including blaze-http and http4s-blaze-server users, are affected. Blaze, accepts connections unconditionally on a dedicated thread pool. This has the net effect of amplifying degradation in services that are unable to handle their current request load, since incoming connections are still accepted and added to an unbounded queue. Each connection allocates a socket handle, which drains a scarce OS resource. This can also confound higher level circuit breakers which work based on detecting failed connections. The vast majority of affected users are using it as part of http4s-blaze-server <= 0.21.16. http4s provides a mechanism for limiting open connections, but is enforced inside the Blaze accept loop, after the connection is accepted and the socket opened. Thus, the limit only prevents the number of connections which can be simultaneously processed, not the number of connections which can be held open. Patches The issue is fixed in…
Recommended action: Upgrade to 0.14.15 or later, then redeploy and verify.A vendor fix does not resolve your finding until you verify it in your own systems.