SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2017-18106

The identifier_hash for a session token in Atlassian Crowd before version 2.9.1 could potentially collide with an identifier_hash for another user or a user in a different directory, this allows remote attackers who can authenticate to Crowd or an…

HIGH 7.5EPSS 1.23%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.23%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The identifier_hash for a session token in Atlassian Crowd before version 2.9.1 could potentially collide with an identifier_hash for another user or a user in a different directory, this allows remote attackers who can authenticate to Crowd or an application using Crowd for authentication to gain access to another user's session provided they can make their identifier hash collide with another user's session identifier hash.

CVSS 3.0
7.5 HIGHCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS
1.23% probability · 69th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-287
Affected
atlassian/crowd
Source
security@atlassian.com
EPSS trend
0%3%5%27 October 2026: 1.23%27 October 202627 October 2026

EPSS 1.2% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.