CVE-2021-26076

The jira.editor.user.mode cookie set by the Jira Editor Plugin in Jira Server and Data Center before version 8.5.12, from version 8.6.0 before version 8.13.4, and from version 8.14.0 before version 8.15.0 allows remote anonymous attackers who can perform an attacker in the middle attack to learn which mode a user is editing in due to the cookie not being set with a secure attribute if Jira was configured to use https.

Published: 2021-04-14 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-26076 is rated Low Risk (38.6/100): CVSS Low severity, with medium exploitation likelihood (EPSS 1.23%). EPSS rose +1.02% over the last day, indicating growing attacker interest. Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2021-26076

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 0.21% 1.23% +1.02%
2 2025-12-22 0.33% 0.21% -0.11%
3 2025-11-21 — 0.33% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26076

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.7 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 1.4 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-26076

Affected software / configurations for CVE-2021-26076

Vendor Product Version Raw CPE
atlassian data_center < 8.5.12 cpe:2.3:a:atlassian:data_center:*:*:*:*:*:*:*:*
atlassian jira < 8.5.12 cpe:2.3:a:atlassian:jira:*:*:*:*:*:*:*:*
atlassian jira_data_center >= 8.6.0, < 8.13.4 cpe:2.3:a:atlassian:jira_data_center:*:*:*:*:*:*:*:*
atlassian jira_data_center >= 8.14.0, < 8.15.1 cpe:2.3:a:atlassian:jira_data_center:*:*:*:*:*:*:*:*
atlassian jira_server >= 8.6.0, < 8.13.4 cpe:2.3:a:atlassian:jira_server:*:*:*:*:*:*:*:*
atlassian jira_server >= 8.14.0, < 8.15.1 cpe:2.3:a:atlassian:jira_server:*:*:*:*:*:*:*:*

References for CVE-2021-26076

URL Tags
https://jira.atlassian.com/browse/JRASERVER-72252 Patch Vendor Advisory
cvelogic Threat Intelligence