CVE-2021-43980Apache Tomcat: Information disclosure
- 3.7LowCVSS base score
- 2.4%Exploitation in 30 daysEPSS · top 16% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
The simplified implementation of blocking reads and writes introduced in Tomcat 10 and back-ported to Tomcat 9.0.47 onwards exposed a long standing (but extremely hard to trigger) concurrency bug in Apache Tomcat 10.1.0 to 10.1.0-M12, 10.0.0-M1 to 10.0.18, 9.0.0-M1 to 9.0.60 and 8.5.0 to 8.5.77 that could cause client connections to share an Http11Processor instance resulting in responses, or part responses, to be received by the wrong client.
Timeline
ID reserved
By apache
- 11 months later
· 11 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Low3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N |
| NVDNVD · Modified | 3.1 | Low3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N |
- EPSS (exploitation in 30 days)
- 2.4% · top 16% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Low 3.7.
Affected products
Apache Software Foundation · Apache Tomcat
- affected 10.1.0-M1 to 10.1.0-M12
- affected 10.0.0-M1 to 10.0.18
- affected 9.0.0-M1 to 9.0.60
- affected 8.5.0 to 8.5.77
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavenorg.apache.tomcat:tomcatGHSA-jx7c-7mj5-9438 (opens in a new tab)
References
References4
- https://lists.apache.org/thread/3jjqbsp6j88b198x5rmg99b1qr8ht3g3 (opens in a new tab)x_transferred
- [oss-security] 20220928 CVE-2021-43980: Apache Tomcat: Information disclosure (opens in a new tab)mailing-listx_transferred
- [debian-lts-announce] 20221026 [SECURITY] [DLA 3160-1] tomcat9 security update (opens in a new tab)mailing-listx_transferred
- DSA-5265 (opens in a new tab)vendor-advisoryx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2022-6865 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-jx7c-7mj5-9438 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-43980)Record last updated .