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CVE-2021-3859A flaw was found in Undertow that tripped the client-side invocation timeout with certain calls made over HTTP2. This flaw allows an…
- 7.5HighCVSS base score
- 1.8%Exploitation in 30 daysEPSS · top 21% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A flaw was found in Undertow that tripped the client-side invocation timeout with certain calls made over HTTP2. This flaw allows an attacker to carry out denial of service attacks.
Timeline
ID reserved
By redhat
- 11 months later
· 11 months later
Published
- 24 months later
· 24 months 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 |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.8% · top 21% of all CVEs (12 Nov 2026)
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
undertow
- affected Fixed in 2.2.15.Final
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavenio.undertow:undertow-coreGHSA-339q-62wm-c39w (opens in a new tab)
References
References6
- https://bugzilla.redhat.com/show_bug.cgi?id=2010378 (opens in a new tab)x_transferred
- https://issues.redhat.com/browse/UNDERTOW-1979 (opens in a new tab)x_transferred
- https://github.com/undertow-io/undertow/pull/1296 (opens in a new tab)x_transferred
- https://github.com/undertow-io/undertow/commit/e43f0ada3f4da6e8579e0020cec3cb1a81e487c2 (opens in a new tab)x_transferred
- https://access.redhat.com/security/cve/CVE-2021-3859 (opens in a new tab)x_transferred
- https://security.netapp.com/advisory/ntap-20221201-0004/ (opens in a new tab)x_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-2022-6212 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-339q-62wm-c39w (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-2021-3859)Record last updated .