CVE-2021-36780 | Unauthorized data access from replicas through vulnerable instance manager pods

A Missing Authentication for Critical Function vulnerability in longhorn of SUSE Longhorn allows attackers to connect to a longhorn-engine replica instance granting it the ability to read and write data to and from a replica that they should not have access to. This issue affects: SUSE Longhorn longhorn versions prior to 1.1.3; longhorn versions prior to 1.2.3v.

Published: 2021-12-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-36780 is rated Moderate Risk (45.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.45%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-36780

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.14% 0.45% +0.31%
2 2025-03-30 0.30% 0.14% -0.16%
3 2025-03-29 — 0.30% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-36780

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.1 HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 5.2 [email protected]
8.1 3.1 HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 5.2 [email protected]
4.8 2.0 MEDIUM
AV:A/AC:L/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:A)
Requires access to an adjacent network segment.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 6.5 4.9 [email protected]

Weakness enumeration for CVE-2021-36780

OS Trackers for CVE-2021-36780

vendor priority summary link
suse high — https://www.suse.com/security/cve/CVE-2021-36780/

Affected software / configurations for CVE-2021-36780

Vendor Product Version Raw CPE
linuxfoundation longhorn < 1.1.3 cpe:2.3:a:linuxfoundation:longhorn:*:*:*:*:*:*:*:*
linuxfoundation longhorn >= 1.2.0, < 1.2.3 cpe:2.3:a:linuxfoundation:longhorn:*:*:*:*:*:*:*:*

References for CVE-2021-36780

cvelogic Threat Intelligence