CVE-2021-47793: Telegram Desktop 2.9.2 contains a denial of service vulnerability that allows attackers to crash the applicati

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HIGH 7.5REMOTEDOWNGRADE

CVE-2021-47793 is a high-severity flaw (CVSS 7.5) affecting telegram desktop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Telegram Desktop 2.9.2 contains a denial of service vulnerability that allows attackers to crash the application by sending an oversized message payload. Attackers can generate a 9 million byte buffer and paste it into the messaging interface to trigger an application crash.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-770
Published	2026-01-16
Last modified	2026-06-17

Publisher (CNA): VulnCheck · Vendor: telegram

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-01-16 00:16 UTCPublished CVE record published
2026-06-17 04:18 UTCUpdated Record last modified

telegram telegram desktop DOWNGRADE

Affected: 2.9.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.9.2

1. Check installed version

apt-cache policy telegram-desktop || rpm -q telegram-desktop || telegram-desktop --version

2. No fixed release: DOWNGRADE to a release before 2.9.2 (Debian / Ubuntu)

apt-cache madison telegram-desktop sudo apt install telegram-desktop=<VERSION_BEFORE_2.9.2> sudo apt-mark hold telegram-desktop

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list telegram-desktop sudo dnf downgrade telegram-desktop-<VERSION_BEFORE_2.9.2> sudo dnf versionlock add telegram-desktop

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-47793?

telegram desktop: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-47793 being exploited?

CVE-2021-47793 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-47793 affect?

CVE-2021-47793 affects telegram desktop. Severity is high (CVSS 7.5). Telegram Desktop 2.9.2 contains a denial of service vulnerability that allows attackers to crash the application by sending an oversized message payload. Attackers can generate a 9 million byte buffer and paste it into the messaging interfa

How urgent is CVE-2021-47793?

Priority 47/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Telegram vulnerabilities

References

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