MIT Kerberos 5 (aka krb5) before 1.17.2 and 1.18.x before 1.18.3 allows unbounded recursion via an ASN.1-encoded Kerberos message because the lib/krb5/asn.1/asn1_encode.c support for BER indefinite lengths lacks a recursion limit.
CVE-2020-28196
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 90.1%
- KEV
- Not listed
Published
November 6, 2020
Last Modified
December 3, 2025
References (28)
- cve@mitrehttps://github.com/krb5/krb5/commit/57415dda6cf04e73ffc3723be518eddfae599bfd
- cve@mitrehttps://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
- cve@mitrehttps://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2020/11/msg00011.html
- cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/45KKOZQWIIIW5C45PJVGQ32AXBSYNBE7/
- cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/73IGOG6CZAVMVNS4GGRMOLOZ7B6QVA7F/
- cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KPH2V3WSQTELROZK3GFCPQDOFLKIZ6H5/
- cve@mitrehttps://security.gentoo.org/glsa/202011-17
- cve@mitrehttps://security.netapp.com/advisory/ntap-20201202-0001/
- cve@mitrehttps://security.netapp.com/advisory/ntap-20210513-0002/
- cve@mitrehttps://www.debian.org/security/2020/dsa-4795
- cve@mitrehttps://www.oracle.com//security-alerts/cpujul2021.html
- cve@mitrehttps://www.oracle.com/security-alerts/cpuApr2021.html
- cve@mitrehttps://www.oracle.com/security-alerts/cpuapr2022.html
- af854a3a-2127-422b-91ae-364da2661108https://github.com/krb5/krb5/commit/57415dda6cf04e73ffc3723be518eddfae599bfd
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | libkrb5support0 (1.17-10ubuntu0.1) @ groovy | 2026-05-23 | ubuntu |
| redhat | redhat-virtualization-host-0:4.4.6-20210527.3.el8_4 | 2021-06-03 | redhat |
| redhat | krb5-0:1.18.2-8.el8 | 2021-05-18 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(4)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
- Microsoft MSRCCVE-2020-281962021-10-15
MIT Kerberos 5 (aka krb5) before 1.17.2 and 1.18.x before 1.18.3 allows unbounded recursion via an ASN.1-encoded Kerberos message because the lib/krb5/asn.1/asn1_encode.c support for BER indefinite lengths lacks a recursion limit.
- Red HatRHSA-2021:1593MODERATE2020-11-06
RHSA-2021:1593 — Moderate
- Red HatRHSA-2021:2239MODERATE2020-11-06
RHSA-2021:2239 — Moderate
- UbuntuUSN-4635-1MEDIUM
Kerberos vulnerability
Data Freshness Timeline
(refreshed 9× in last 7d / 37× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:25 UTCEPSS rescore
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- 2026-06-24 09:29 UTCOSV refresh
- 2026-06-23 21:31 UTCEPSS rescore
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- 2026-06-21 14:54 UTCEPSS rescore
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- 2026-06-07 15:23 UTCEPSS rescore
- 2026-06-07 13:30 UTCOSV refresh
- 2026-06-06 13:46 UTCEPSS rescore
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- 2026-06-01 13:50 UTCEPSS rescore
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- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-23 05:37 UTCEG score recompute
- 2026-05-23 05:37 UTCVendor advisory
- 2026-05-23 05:37 UTCGHSA enrichment
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Frequently asked(5)
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