CVE-2021-27351

The Terminate Session feature in the Telegram application through 7.2.1 for Android, and through 2.4.7 for Windows and UNIX, fails to invalidate a recently active session.

Published: 2021-02-19 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-27351 is rated Moderate Risk (40.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.84%). 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-2021-27351

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 0.18% 0.84% +0.66%
2 2025-05-24 0.26% 0.18% -0.08%
3 2025-03-30 — 0.26% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-27351

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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: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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-27351

OS Trackers for CVE-2021-27351

vendor priority summary link
debian not yet assigned CVE-2021-27351 not yet assigned priority: Debian including 1 source packages (telegram-desktop), 4 status rows across 4 suites (bookworm, bullseye, forky, sid): resolved 4. https://security-tracker.debian.org/tracker/CVE-2021-27351
gentoo low CVE-2021-27351: 1 GLSA(s) (202105-07), 2 atom(s) (net-im/telegram-desktop, net-im/telegram-desktop-bin); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-27351
ubuntu low CVE-2021-27351 low priority: Ubuntu including 1 source packages (telegram-desktop), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 8, ignored 4, needs-triage 3, released 1. https://ubuntu.com/security/CVE-2021-27351

Affected software / configurations for CVE-2021-27351

Vendor Product Version Raw CPE
telegram telegram <= 2.4.7 cpe:2.3:a:telegram:telegram:*:*:*:*:*:unix:*:*
telegram telegram <= 2.4.7 cpe:2.3:a:telegram:telegram:*:*:*:*:*:windows:*:*
telegram telegram <= 7.2.1 cpe:2.3:a:telegram:telegram:*:*:*:*:*:android:*:*

References for CVE-2021-27351

cvelogic Threat Intelligence