cbcvebase.
CVE-2019-17638
published 2020-07-09

CVE-2019-17638: In Eclipse Jetty, versions 9.4.27.v20200227 to 9.4.29.v20200521, in case of too large response headers, Jetty throws an exception to produce an HTTP 431 error…

PriorityP259critical9.4CVSS 3.1
AVNACLPRNUINSUCHIHAL
EPSS
11.14%
95.5th percentile
In Eclipse Jetty, versions 9.4.27.v20200227 to 9.4.29.v20200521, in case of too large response headers, Jetty throws an exception to produce an HTTP 431 error. When this happens, the ByteBuffer containing the HTTP response headers is released back to the ByteBufferPool twice. Because of this double release, two threads can acquire the same ByteBuffer from the pool and while thread1 is about to use the ByteBuffer to write response1 data, thread2 fills the ByteBuffer with other data. Thread1 then proceeds to write the buffer that now contains different data. This results in client1, which issued request1 seeing data from another request or response which could contain sensitive data belonging to client2 (HTTP session ids, authentication credentials, etc.). If the Jetty version cannot be upgraded, the vulnerability can be significantly reduced by configuring a responseHeaderSize significantly larger than the requestHeaderSize (12KB responseHeaderSize and 8KB requestHeaderSize).

Affected

8 ranges
VendorProductVersion rangeFixed in
debianjetty9< jetty9 9.4.31-1 (bookworm)jetty9 9.4.31-1 (bookworm)
eclipsejetty
eclipsejetty
eclipsejetty
jenkinsjenkins_core
jenkinsjenkins_lts
jenkinsjenkins_weekly
the_eclipse_foundationeclipse_jetty

Detection & IOCsextracted from sources · hover to see the quote

  • Trigger condition: sending HTTP request headers large enough to cause Jetty to return HTTP 431 (Request Header Fields Too Large) can expose response data from other clients due to ByteBuffer double-release race condition
  • Sensitive data leakage observable in HTTP responses: watch for HTTP session IDs or authentication credentials appearing in responses to unrelated requests, indicating ByteBuffer cross-contamination
  • Affected Jenkins versions (core, bundled Jetty 9.4.27): Jenkins weekly 2.224–2.242 and LTS 2.222.1–2.235.4 are vulnerable; unauthenticated exploitation possible over HTTP
  • Affected Jetty version range: 9.4.27.v20200227 through 9.4.29.v20200521; flag any server advertising these Jetty versions in HTTP Server headers
  • Exploitation vector is remote, unauthenticated, over HTTP — no authentication required to trigger the vulnerability
  • ·Mitigation (not a fix): set responseHeaderSize significantly larger than requestHeaderSize to reduce exploitation likelihood — recommended values are 12KB responseHeaderSize and 8KB requestHeaderSize
  • ·Jenkins instances started via 'java -jar jenkins.war' (installers/packages) are affected; instances deployed in servlet containers such as Tomcat are NOT affected by the bundled Jetty vulnerability

CVSS provenance

nvdv3.19.4CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
osv9.4CRITICAL
vendor_debian9.4CRITICAL
vendor_oracle9.4CRITICAL
vendor_redhat9.4CRITICAL
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