CVE-2020-27846
XML Processing error in github.com/crewjam/saml
A signature verification vulnerability exists in crewjam/saml. This flaw allows an attacker to bypass SAML Authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
9.8
A signature verification vulnerability exists in crewjam/saml. This flaw allows an attacker to bypass SAML Authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
- Record
CVE-2020-27846- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 10.0 High
AV:N/AC:L/Au:N/C:C/I:C/A:C - Weakness
- CWE-115
- Updated
- 2026-11-02
CVE List No score
A signature verification vulnerability exists in crewjam/saml. This flaw allows an attacker to bypass SAML Authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
- Record
CVE-2020-27846- Weakness
- CWE-115
- Updated
- 2026-11-02
EUVDEUVD-2021-1260 No score
A signature verification vulnerability exists in crewjam/saml. This flaw allows an attacker to bypass SAML Authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
- Record
EUVD-2021-1260- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4hq8-gmxx-h6w9
9.8
XML Processing error in github.com/crewjam/saml
Impact
There are three vulnerabilities in the go encoding/xml package that can allow an attacker to forge part of a signed XML document. For details on this vulnerability see xml-roundtrip-validator
Patches
In version 0.4.3, all XML input is validated prior to being parsed.
- Record
GHSA-4hq8-gmxx-h6w9- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-115, CWE-287
- Updated
- 2026-11-02
OSV
9.8
A signature verification vulnerability exists in crewjam/saml. This flaw allows an attacker to bypass SAML Authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
- Record
CVE-2020-27846- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVGHSA-4hq8-gmxx-h6w9
9.8
XML Processing error in github.com/crewjam/saml
Impact
There are three vulnerabilities in the go encoding/xml package that can allow an attacker to forge part of a signed XML document. For details on this vulnerability see xml-roundtrip-validator
Patches
In version 0.4.3, all XML input is validated prior to being parsed.
- Record
GHSA-4hq8-gmxx-h6w9- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-115, CWE-287
- Updated
- 2026-11-02
Show 5 moreShow less
OSVOESA-2021-1445
9.8
grafana security update
Grafana is an open source, feature rich metrics dashboard and graph editor for Graphite, InfluxDB & OpenTSDB.
Security Fix(es):
Grafana before 7.1.0-beta 1 allows XSS via a query alias for the ElasticSearch datasource.(CVE-2020-24303)
A signature verification vulnerability exists in crewjam/saml. This flaw allows an attacker to bypass SAML Authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.(CVE-2020-27846)
The snapshot feature in Grafana 6.7.3 through 7.4.1 can allow an unauthenticated remote attackers to trigger a Denial of Service via a remote API call if a commonly used configuration is set.(CVE-2021-27358)
One of the usage insights HTTP API endpoints in Grafana Enterprise 6.x before 6.7.6, 7.x before 7.3.10, and 7.4.x before 7.4.5 is accessible without any authentication. This allows any unauthenticated user to send an unlimited number of requests to the endpoint, leading to a denial of service (DoS) attack against a Grafana Enterprise instance.(CVE-2021-28148)
The team sync HTTP API in Grafana Enterprise 6.x before 6.7.6, 7.x before 7.3.10, and 7.4.x before 7.4.5 has an Incorrect Access Control issue. On Grafana instances using an external authentication service and having the EditorsCanAdmin feature enabled, this vulnerability allows any authenticated user to add external groups to any existing team. This can be used to grant a user team permissions that the user isn't supposed to have.(CVE-2021-28147)
Grafana is an open source data visualization platform. In affected versions unauthenticated and authenticated users are able to view the snapshot with the lowest database key by accessing the literal paths: /dashboard/snapshot/:key, or /api/snapshots/:key. If the snapshot "public_mode" configuration setting is set to True (vs default of False), unauthenticated users are able to delete the snapshot with the lowest database key by accessing the literal path: /api/snapshots-delete/:deleteKey. Regardless of the snapshot "public_mode" setting, authenticated users are able to delete the snapshot with the lowest database key by accessing the literal paths: /api/snapshots/:key, or /api/snapshots-delete/:deleteKey. The combination of deletion and viewing enables a complete walk through all snapshot data while resulting in complete snapshot data loss. This issue has been resolved in versions 8.1.6 and 7.5.11. If for some reason you cannot upgrade you can use a reverse proxy or similar to block access to the literal paths: /api/snapshots/:key, /api/snapshots-delete/:deleteKey, /dashboard/snapshot/:key, and /api/snapshots/:key. They have no normal function and can be disabled without side effects.(CVE-2021-39226)
- Record
OESA-2021-1445- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVRHSA-2021:1859
9.8
Red Hat Security Advisory: grafana security, bug fix, and enhancement update
- Record
RHSA-2021:1859- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVRLSA-2021:1859
9.8
Moderate: grafana security, bug fix, and enhancement update
Grafana is an open source, feature rich metrics dashboard and graph editor for Graphite, InfluxDB & OpenTSDB.
The following packages have been upgraded to a later upstream version: grafana (7.3.6). (BZ#1850471)
Security Fix(es):
-
crewjam/saml: authentication bypass in saml authentication (CVE-2020-27846)
-
grafana: XSS via a query alias for the Elasticsearch and Testdata datasource (CVE-2020-24303)
For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.
Additional Changes:
For detailed information on changes in this release, see the Rocky Linux 8.4 Release Notes linked from the References section.
- Record
RLSA-2021:1859- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVBIT-grafana-2020-27846 No score
A signature verification vulnerability exists in crewjam/saml. This flaw allows an attacker to bypass SAML Authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.
- Record
BIT-grafana-2020-27846- Updated
- 2026-11-02
OSVGO-2021-0058 No score
Signature validation bypass due to XML processing error in github.com/crewjam/saml
Due to the behavior of encoding/xml, a crafted XML document may cause XML Digital Signature validation to be entirely bypassed, causing an unsigned document to appear signed.
- Record
GO-2021-0058- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/crewjam/samlGo |
before 0.4.3 | 0.4.3 |
grafanaBitnami |
before 6.7.5, 7.0.0 up to 7.2.3, 7.3.0 up to 7.3.6 | 6.7.57.2.37.3.6 |
grafanaopenEuler:20.03-LTS-SP1 From an advisory covering 6 CVEs |
before 7.5.11-1.oe1 | 7.5.11-1.oe1 |
grafanaopenEuler:20.03-LTS-SP2 From an advisory covering 6 CVEs |
before 7.5.11-1.oe1 | 7.5.11-1.oe1 |
grafanaRed Hat:enterprise_linux:8::appstream From an advisory covering 2 CVEs |
before 0:7.3.6-2.el8 | 0:7.3.6-2.el8 |
grafana-debuginfoRed Hat:enterprise_linux:8::appstream From an advisory covering 2 CVEs |
before 0:7.3.6-2.el8 | 0:7.3.6-2.el8 |
grafanaRocky Linux:8 From an advisory covering 2 CVEs |
before 0:7.3.6-2.el8 | 0:7.3.6-2.el8 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-27846 is a critical vulnerability (CVSS 9.8) in Saml Project Saml, published December 21, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 4.93%, the 92nd percentile. Fixed in github.com/crewjam/saml 0.4.3.
References
bugzilla.redhat.com/show_bug.cgi?id=1907670
mattermost.com/blog/coordinated-disclosure-go-xml-vulnerabilities
github.com/crewjam/saml/security/advisories/GHSA-4hq8-gmxx-h6w9
grafana.com/blog/2020/12/17/grafana-6.7.5-7.2.3-and-7.3.6-released-with-important-security-fix-for-grafana-enterprise
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3YUTKIRWT6TWU7DS6GF3EOANVQBFQZYI
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ICP3YRY2VUCNCF2VFUSK77ZMRIC77FEM
Show 28 moreShow less
security.netapp.com/advisory/ntap-20210205-0002
nvd.nist.gov/vuln/detail/CVE-2020-27846
github.com/crewjam/saml/commit/da4f1a0612c0a8dd0452cf8b3c7a6518f6b4d053
pkg.go.dev/vuln/GO-2021-0058
lists.fedoraproject.org/archives/list/[email protected]/message/3YUTKIRWT6TWU7DS6GF3EOANVQBFQZYI
lists.fedoraproject.org/archives/list/[email protected]/message/ICP3YRY2VUCNCF2VFUSK77ZMRIC77FEM
github.com/advisories/GHSA-4hq8-gmxx-h6w9
github.com/crewjam/saml
openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2021-1445
nvd.nist.gov/vuln/detail/CVE-2020-24303
nvd.nist.gov/vuln/detail/CVE-2021-27358
nvd.nist.gov/vuln/detail/CVE-2021-28148
nvd.nist.gov/vuln/detail/CVE-2021-28147
nvd.nist.gov/vuln/detail/CVE-2021-39226
access.redhat.com/errata/RHSA-2021:1859
access.redhat.com/security/updates/classification
access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.4_release_notes
bugzilla.redhat.com/show_bug.cgi?id=1843170
bugzilla.redhat.com/show_bug.cgi?id=1850471
bugzilla.redhat.com/show_bug.cgi?id=1892418
bugzilla.redhat.com/show_bug.cgi?id=1916083
security.access.redhat.com/data/csaf/v2/advisories/2021/rhsa-2021_1859.json
access.redhat.com/security/cve/CVE-2020-24303
cve.org/CVERecord?id=CVE-2020-24303
github.com/grafana/grafana/pull/25401
access.redhat.com/security/cve/CVE-2020-27846
cve.org/CVERecord?id=CVE-2020-27846
errata.rockylinux.org/RLSA-2021:1859