CVE-2019-16782
No exploitation reported by the sources we read.
- Published2019-12-18
- Fixed in2.0.8 · 1.6.12
- WeaknessCWE-203 · CWE-208
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
There's a possible information leak / session hijack vulnerability in Rack (RubyGem rack). This vulnerability is patched in versions 1.6.12 and 2.0.8. Attackers may be able to find and hijack sessions by using timing attacks targeting the session id. Session ids are usually stored and indexed in a database that uses some kind of scheme for speeding up lookups of that session id. By carefully measuring the amount of time it takes to look up a session, an attacker may be able to find a valid session id and hijack the session. The session id itself may be generated randomly, but the way the session is indexed by the backing store does not use a secure comparison.
Timeline
dates in UTC- 2019-12-1820:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-16782?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-16782?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 |
|---|---|---|---|
| 2.0 | ≥ 2.0.0, < 2.0.8 | 2.0.8 | NVD · OSV |
| 1.6 | < 1.6.12 | 1.6.12 | NVD · OSV |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 31.x | = 31 | no fix published | NVD |
| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 15.1 | = 15.1 | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Rack to 2.0.8 · 1.6.12
Advisories and patches
- www.openwall.comPatch
- github.comPatch
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Published
- 2019-12-18
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2019-16782?
Is CVE-2019-16782 actively exploited?
What is the CVSS score for CVE-2019-16782?
Running rack? Hear about its next vulnerability
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.