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Telegram CVE-2021-37596

MEDIUM
Cross-site Scripting (XSS) (CWE-79)
2021-07-30 cve@mitre.org
6.1
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 6.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required.

Exploit ScenarioDerived

A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.6% exploitation probability (EPSS)

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AnalysisAI

Telegram Web K Alpha 0.6.1 allows XSS via a document name. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Cross-Site Scripting (XSS) vulnerability could allow attackers to inject malicious scripts into web pages viewed by other users.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. Affected products include: Telegram Web K Alpha.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.1 MEDIUM
AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionNVD

Telegram Web K Alpha 0.6.1 allows XSS via a document name.

Threat Intelligence Overview

EPSS Score
0.6%
Top 54% exploitable
Data Quality
3 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.6%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

31
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +30
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

Affected Products (CPE)NVD

cpe:2.3:a:telegram:web_k_alpha:0.6.1:*:*:*:*:*:*:*
CVE-2019-10044 HIGH POC
8.8 Mar 25

Telegram Desktop before 1.5.12 on Windows, and the Telegram applications for Android, iOS, and Linux, is vulnerable to a

CVE-2026-107181 HIGH POC
8.6 Oct 07

One-click account takeover in Telegram Desktop before 7.2.9, where the Core::Sandbox inter-process communication layer f

CVE-2026-94488 HIGH POC
8.3 Sep 21

Telegram Desktop before 6.9.4 fails to escape inline-keyboard button text when a chat is exported to HTML, so attacker-c

CVE-2018-20436 HIGH POC
8.1 Dec 24

The "secret chat" feature in Telegram 4.9.1 for Android has a "side channel" in which Telegram servers send GET requests

CVE-2021-47793 HIGH POC
7.5 Jan 16

Telegram Desktop versions up to 2.9.2 is affected by allocation of resources without limits or throttling (CVSS 7.5).

CVE-2018-17231 HIGH POC
7.5 Sep 19

Telegram Desktop (aka tdesktop) 1.3.14 might allow attackers to cause a denial of service (assertion failure and applica

CVE-2021-31321 HIGH POC
7.1 May 18

Telegram Android <7.1.0 (2090), Telegram iOS <7.1, and Telegram macOS <7.1 are affected by a Stack Based Overflow in the

CVE-2021-31320 HIGH POC
7.1 May 18

Telegram Android <7.1.0 (2090), Telegram iOS <7.1, and Telegram macOS <7.1 are affected by a Heap Buffer Overflow in the

CVE-2018-17780 MEDIUM POC
6.5 Sep 29

Telegram Desktop (aka tdesktop) 1.3.14, and Telegram 3.3.0.0 WP8.1 on Windows, leaks end-user public and private IP addr

CVE-2022-43363 MEDIUM POC
6.1 Dec 06

Telegram Web 15.3.1 allows XSS via a certain payload derived from a Target Corporation website. Rated medium severity (C

CVE-2021-40532 CRITICAL
9.8 Sep 06

Telegram Web K Alpha before 0.7.2 mishandles the characters in a document extension. Rated critical severity (CVSS 9.8),

CVE-2018-17613 CRITICAL
9.8 Sep 28

Telegram Desktop (aka tdesktop) 1.3.16 alpha, when "Use proxy" is enabled, sends credentials and application data in cle

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