Vulnerability · Published Jul 28, 2026 · Assigned by GitHub_M

CVE-2026-54638td has pre-auth denial of service via unbounded memory allocation in proto.UnencryptedMessage.Decode

High 7.5

In plain English

A high-severity resource allocation without limits in td from gotd. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 49.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

gotd/td is a T Telegram MTProto API client in Go. Prior to 0.145.1, proto.UnencryptedMessage.Decode in proto/unencrypted_message.go read attacker controlled dataLen from an unauthenticated MTProto unencrypted packet and allocated make([]byte, dataLen) before checking the remaining buffer, allowing remote unauthenticated denial of service through excessive memory allocation and CPU or garbage collection pressure. This issue is fixed in version 0.145.1.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/gotd/td	0.145.1	GHSA-whmm-qj9r-wvr2
Go	github.com/gotd/td	0.145.1	GO-2026-6138

Affected products (as reported)

Vendor	Product	Versions
gotd	td	< 0.145.1

Weakness: CWE-770, CWE-789 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/gotd/td/security/advisories/GHSA-whmm-qj9r-wvr2 x_refsource_CONFIRM
https://github.com/gotd/td/issues/1711 x_refsource_MISC
https://github.com/gotd/td/commit/9d5d1f31ea5022d9798d84ccce15de2e91ba6baa x_refsource_MISC
https://github.com/gotd/td/releases/tag/v0.145.1 x_refsource_MISC