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CVE-2020-17527

34
FAUCET Score

CVE-2020-17527 describes an information leakage vulnerability in Apache Tomcat versions 10.0.0-M1 to 10.0.0-M9, 9.0.0-M1 to 9.0.39, and 8.5.0 to 8.5.59, where HTTP/2 connections could re-use a header value from a previous stream for a subsequent request. This vulnerability is rated High severity (CVSS 7.5) due to its network attack vector and potential for high confidentiality impact (CWE-200), though it would likely cause connection errors. There is currently no evidence of active exploitation, publicly available exploit code, or significant community discussion or media coverage for this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 8.5.1, <= 8.5.59CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
>= 9.0.1, <= 9.0.35CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:9.0.0:milestone10:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:9.0.0:milestone11:*:*:*:*:*:*
9.0.0CPE matchmatch criteria
cpe:2.3:a:apache:tomcat:9.0.0:milestone12:*:*:*:*:*:*

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:H/I:N/A:N

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

Exploit Intelligence

EPSS Score
24.62%
Probability of exploitation in next 30 days
EPSS Percentile
97.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.2462 is in the 96th percentile among its peer group of 51,485 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 (14)

mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcat-coyoteFixed in: 9.0.40
mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcat-coyoteFixed in: 8.5.60
mavenpatch availablevia ghsa
Product: org.apache.tomcat:tomcat-coyoteFixed in: 10.0.0-M10
microsoftpatch availablevia msrc
Product: 19196-16823Fixed in: 9.0.39-6
microsoftpatch availablevia msrc
Product: 19197-16823Fixed in: 9.0.39-5
oraclepatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Support for Spring Boot 2.4.9Fixed in: tomcat
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5Fixed in: tomcat
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Fuse 7.10Fixed in: tomcat
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 7Fixed in: jws5-tomcat-0:9.0.36-9.redhat_8.1.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 7Fixed in: jws5-tomcat-native-0:1.2.25-3.redhat_3.el7jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 8Fixed in: jws5-tomcat-0:9.0.36-9.redhat_8.1.el8jws
View patch
redhatpatch availablevia redhat_api
Product: Red Hat JBoss Web Server 5.4 on RHEL 8Fixed in: jws5-tomcat-native-0:1.2.25-3.redhat_3.el8jws
View patch
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: pki-deps:10.6/pki-servlet-engine

Vendor Advisories (3)

mavenGHSA-vvw4-rfwf-p6hxhigh

Exposure of Sensitive Information to an Unauthorized Actor in Apache Tomcat

Feb 9, 2022
microsoft2020-Dec/CVE-2020-17527Important

Apache Tomcat: Request header mix-up between HTTP/2 streams

Dec 8, 2020
redhatCVE-2020-17527Moderate

tomcat: HTTP/2 request header mix-up

Dec 3, 2020

References

lists.apache.org / thread.html/r26a2a66339087fc37db3caf201e446d3e83b5cce314371e235ff1784%40%3Ccommits.tomee.apache.org%3E
lists.apache.org / thread.html/r2d6e05c5ff96f8068a59dfdb3800e9ee8d4e36ce1971783c6e5f9b20%40%3Ccommits.tomee.apache.org%3E
lists.apache.org / thread.html/r5a285242737ddef4d338236328aaaf3237183e1465a5efafd16b99ed%40%3Cdev.tomcat.apache.org%3E
lists.apache.org / thread.html/r8a227ac6a755a6406c1cc47dd48800e973d4cf13fe7fe68ac59c679c%40%3Cdev.tomcat.apache.org%3E
lists.apache.org / thread.html/r9fd47f1b03e9b41d16a5cf72659b533887267d3398d963c2fff3abfa%40%3Ccommits.tomee.apache.org%3E
lists.apache.org / thread.html/ra35c8d617b17d59f400112cebadec43ad379f98198b4a9726190d7ee%40%3Cissues.guacamole.apache.org%3E
lists.apache.org / thread.html/ra9fcdb904dd2e2256ef90b3e4ced279cd464cb0ab63a6c64df5c010d%40%3Cannounce.apache.org%3E
lists.apache.org / thread.html/ra9fcdb904dd2e2256ef90b3e4ced279cd464cb0ab63a6c64df5c010d%40%3Cannounce.tomcat.apache.org%3E
lists.apache.org / thread.html/raa0e9ad388c1e6fd1e301b5e080f9439f64cb4178119a86a4801cc53%40%3Cdev.tomcat.apache.org%3E
lists.apache.org / thread.html/rabbe6b3ae6a9795641d7a05c00d2378d5bbbe4240b7e20f09b092cce%40%3Cissues.guacamole.apache.org%3E
lists.apache.org / thread.html/rbba08c4dcef3603e36276d49adda8eedbe458c5104314b4038f697e1%40%3Cusers.tomcat.apache.org%3E
lists.apache.org / thread.html/rca833c6d42b7b9ce1563488c0929f29fcc95947d86e5e740258c8937%40%3Cdev.tomcat.apache.org%3E
lists.apache.org / thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.apache.org%3E
lists.apache.org / thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E
Mailing ListVendor Advisory
lists.apache.org / thread.html/rd5babd13d7a350b369b2f647b4dd32ce678af42f9aba5389df1ae6ca%40%3Cusers.tomcat.apache.org%3E
lists.debian.org / debian-lts-announce/2020/12/msg00022.html
Mailing ListThird Party Advisory
security.gentoo.org / glsa/202012-23
Third Party Advisory
security.netapp.com / advisory/ntap-20201210-0003
Third Party Advisory
debian.org / security/2021/dsa-4835
Third Party Advisory
oracle.com / security-alerts/cpuApr2021.html
PatchThird Party Advisory
oracle.com / security-alerts/cpuapr2022.html
PatchThird Party Advisory
oracle.com / security-alerts/cpujan2022.html
PatchThird Party Advisory
oracle.com / /security-alerts/cpujul2021.html
PatchThird Party Advisory
openwall.com / lists/oss-security/2020/12/03/3
Mailing ListThird Party Advisory