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Vulnerability record · CVE-2021-25122 · published 1 March 2021

CVE-2021-25122: Apache tomcat information exposure vulnerability

Apache · Tomcat

When responding to new h2c connection requests, Apache Tomcat versions 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41 and 8.5.0 to 8.5.61 could duplicate request headers and a limited amount of request body from one request to another meaning user A and user B could both see the results of user A's request.

7.5 CVSS 3.1 High EPSS 18% · top 2.9% CWE-200 · Information exposure
7.5CVSS 3.1 base score, v2 5.0
18%EPSS exploitation probability, 30 days
NoNot in CISA KEV
12Affected product versions listed by NVD
36References
25 Aug 2026Last modified by NVD

Description

When responding to new h2c connection requests, Apache Tomcat versions 10.0.0-M1 to 10.0.0, 9.0.0.M1 to 9.0.41 and 8.5.0 to 8.5.61 could duplicate request headers and a limited amount of request body from one request to another meaning user A and user B could both see the results of user A's request.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

12 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.openwall.com/lists/oss-security/2021/03/01/1 Mailing ListThird Party Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.apache.org%
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cdev.tomcat.apache.or
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cusers.tomcat.apache.
https://lists.apache.org/thread.html/rcd90bf36b1877e1310b87ecd14ed7bbb15da52b297efd9f0e7253a3b%40%3Cusers.tomcat.apache.
https://lists.apache.org/thread.html/rd0463f9a5cbc02a485404c4b990f0da452e5ac5c237808edba11c947%40%3Cusers.tomcat.apache.
https://lists.apache.org/thread.html/rf6d5d57b114678d8898005faef31e9fd6d7c981fcc4ccfc3bc272fc9%40%3Cdev.tomcat.apache.or
https://lists.debian.org/debian-lts-announce/2021/03/msg00018.html Mailing ListThird Party Advisory
https://security.gentoo.org/glsa/202208-34 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210409-0002/ Third Party Advisory
https://www.debian.org/security/2021/dsa-4891 Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html PatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/03/01/1 Mailing ListThird Party Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.apache.org%
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cannounce.tomcat.apac Mailing ListVendor Advisory
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cdev.tomcat.apache.or
https://lists.apache.org/thread.html/r7b95bc248603360501f18c8eb03bb6001ec0ee3296205b34b07105b7%40%3Cusers.tomcat.apache.
https://lists.apache.org/thread.html/rcd90bf36b1877e1310b87ecd14ed7bbb15da52b297efd9f0e7253a3b%40%3Cusers.tomcat.apache.
https://lists.apache.org/thread.html/rd0463f9a5cbc02a485404c4b990f0da452e5ac5c237808edba11c947%40%3Cusers.tomcat.apache.
https://lists.apache.org/thread.html/rf6d5d57b114678d8898005faef31e9fd6d7c981fcc4ccfc3bc272fc9%40%3Cdev.tomcat.apache.or
https://lists.debian.org/debian-lts-announce/2021/03/msg00018.html Mailing ListThird Party Advisory
https://security.gentoo.org/glsa/202208-34 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210409-0002/ Third Party Advisory
https://www.debian.org/security/2021/dsa-4891 Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html PatchThird Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-25122), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.