CVE-2023-30540 | Chat poll data can still be queried from API after purging history in Nextcloud talk

Nextcloud Talk is a chat, video & audio call extension for Nextcloud. In affected versions a user that was added later to a conversation can use this information to get access to data that was deleted before they were added to the conversation. This issue has been patched in version 15.0.5 and it is recommended that users upgrad to 15.0.5. There are no known workarounds for this issue.

Published: 2023-04-17 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2023-30540 is rated Low Risk (30.6/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.66%). Mandatory action: 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-2023-30540

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 0.29% 0.66% +0.37%
2 2026-04-21 0.85% 0.29% -0.56%
3 2026-04-19 0.85%

Full EPSS history (34 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-30540

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.5 3.1 LOW
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
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.
2.1 1.4 [email protected]
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
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.
2.8 1.4 [email protected]

Weakness enumeration for CVE-2023-30540

Affected software / configurations for CVE-2023-30540

Vendor Product Version Raw CPE
nextcloud talk >= 15.0.0, < 15.0.5 cpe:2.3:a:nextcloud:talk:*:*:*:*:*:*:*:*

References for CVE-2023-30540

cvelogic Threat Intelligence