CVE-2020-17049: Kerberos KDC Security Feature Bypass Vulnerability
Vulnerability summary
CVE-2020-17049 is a high (CVSS 9.0) Incorrect Authorization vulnerability in microsoft windows server 2008 service pack 2. EPSS estimates a 13.79% chance of exploitation in the next 30 days, higher than 96.5% of scored vulnerabilities.
Not severe (CVSS 6.6, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 7 · Related 3Timeline
- 11-11-2020PublishedVulnerability first disclosed.
- 15-11-2024Last modifiedVulnerability information updated.
Description
A security feature bypass vulnerability exists in the way Key Distribution Center (KDC) determines if a service ticket can be used for delegation via Kerberos Constrained Delegation (KCD). To exploit the vulnerability, a compromised service that is configured to use KCD could tamper with a service ticket that is not valid for delegation to force the KDC to accept it. The update addresses this vulnerability by changing how the KDC validates service tickets used with KCD.
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · Red hatEcosystem advisory · calculated7.2HighCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:HDiffers
- NVDNIST6.6MediumCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
13.79%
Chance of exploitation in the next 30 days
Percentile
97%
Versus all other CVEs
30-day change
No change 0.00 pp
From 13.79% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, administrative account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Microsoft17 products
- windows server 2008 service pack 2≥ 6.0.0, < 6.0.6003.21167
- windows server 2008 r2 service pack 1≥ 6.1.0, < 6.1.7601.25661
- windows server 2008 r2 service pack 1 (server core installation)≥ 6.0.0, < 6.1.7601.25661
- windows server 2008 service pack 2≥ 6.0.0, < 6.0.6003.21167
- windows server 2008 service pack 2 (server core installation)≥ 6.0.0, < 6.0.6003.21167
Redhat16 products
- krb5< 0:1.20.1-8.el9
- krb5-debuginfo< 0:1.20.1-8.el9
- krb5-debugsource< 0:1.20.1-8.el9
- krb5-devel< 0:1.20.1-8.el9
- krb5-libs< 0:1.20.1-8.el9
Samba1 product
- samba≥ 4.1.0, < 4.13.13 | ≥ 4.14.0, < 4.14.9 | ≥ 4.15.0, < 4.15.1
3 vendors · 34 products
References
23 links
- security.gentoo.org/glsa/202309-06Vendor Advisory
