SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-52539

Outstatic CMS <= 2.1.9 contains a hardcoded JWT signing secret.

CRITICAL 9.1EPSS 0.30%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.30%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

Outstatic CMS <= 2.1.9 contains a hardcoded JWT signing secret. When the OST_TOKEN_SECRET environment variable is not set, the application falls back to the default value which is publicly visible in the source code repository. An unauthenticated remote attacker can exploit this by forging JWT session tokens with arbitrary user data and full administrative permissions.

CVSS 3.1
9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS
0.30% probability · 23th percentile
CISA KEV
Not listed
Weakness
CWE-798
Source
cve@mitre.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.