CVE-2020-17527
A public proof of concept exists; no exploitation attested.
- Published2020-12-03
- WeaknessCWE-200
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
While investigating bug 64830 it was discovered that Apache Tomcat 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 could re-use an HTTP request header value from the previous stream received on an HTTP/2 connection for the request associated with the subsequent stream. While this would most likely lead to an error and the closure of the HTTP/2 connection, it is possible that information could leak between requests.
Timeline
dates in UTC- 2020-12-0319:15CVE publishedNVD
- 2026-10-2319:23First public proof of conceptPoC-in-GitHub
- 2026-10-2319:23EPSS crossed 10 %FIRST EPSS
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-17527?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-17527?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD · OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 8.5 | ≥ 8.5.1, ≤ 8.5.59 | no fix published | NVD |
| 9.0 | ≥ 9.0.1, ≤ 9.0.35 | no fix published | NVD |
| 9.0 | = 9.0.0 | no fix published | NVD |
| 9.0 | = 9.0.35-3.39.1 | no fix published | NVD |
| 9.0 | = 9.0.35-3.57.3 | no fix published | NVD |
| 9.0 | = 9.0.36 | no fix published | NVD |
| 9.0 | = 9.0.37 | no fix published | NVD |
| 9.0 | = 9.0.38 | no fix published | NVD |
| 9.0 | = 9.0.39 | no fix published | NVD |
| 10.0 | = 10.0.0 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 17.1 | = 17.1 | no fix published | NVD |
| 17.2 | = 17.2 | no fix published | NVD |
| 17.3 | = 17.3 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 10.0 | ≥ 10.0.0-M1, < 10.0.0-M10 | 10.0.0-M10 | OSV |
| 9.0 | ≥ 9.0.0-M1, < 9.0.40 | 9.0.40 | OSV |
| 8.5 | ≥ 8.5.0, < 8.5.60 | 8.5.60 | OSV |
11 more products in the sources.
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
Advisories and patches
- lists.apache.orgVendor Advisory
- www.oracle.comPatch
- www.oracle.comPatch
- www.oracle.comPatch
- www.oracle.comPatch
Detection
read 2026-10-23 19:23 UTC- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
Sources
- CISA-ADPSSVC decisionnone2026-10-08
- OpenCVESSVC decisionnone—
- NVDCVSS 3.17.5read 2026-10-23
- NVDCVSS 2.05read 2026-10-23
- CNAweakness (CWE)CWE-200read 2026-10-23
- NVDweakness (CWE)CWE-200read 2026-10-23
- FIRST EPSSEPSS score24.6 %read 2026-10-23
- PoC-in-GitHubproof of concept1read 2026-10-23
- OSVaffected packages—
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Published
- 2020-12-03
- Last Modified
- 2026-10-08
- NVD status
- Modified
Frequently asked questions
What is CVE-2020-17527?
Is CVE-2020-17527 actively exploited?
What is the CVSS score for CVE-2020-17527?
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