CVE-2026-54638Published

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

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-54638

Published

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.

Source published: 28 Jul 2026 22:14:53 UTC
Source modified: 29 Jul 2026 14:20:26 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

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CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd · CVE-2026-54638

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-770 · CWE-789

Original publisher date fields

published: 2026-07-28T23:17:08.617

lastModified: 2026-10-23T23:10:00.157

Source published: 28 Jul 2026 23:17:08 UTC
Source modified: 23 Oct 2026 23:10:00 UTC
Observed here: 25 Oct 2026 13:17:28 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

osv · GHSA-whmm-qj9r-wvr2

Published

### Impact A remote, unauthenticated attacker can cause excessive memory allocation (and resulting CPU / GC pressure, potentially OOM termination) by sending a crafted unencrypted MTProto packet. `(*proto.UnencryptedMessage).Decode` read an attacker-controlled 32-bit `dataLen` field and immediately allocated a buffer of that size via `make([]byte, dataLen)` **before** validating that the underlying buffer actually contained that many bytes. A 20-byte packet declaring a ~1.75 GB payload (e.g. `dataLen = 0x70000000`) forces the runtime to provision and zero-initialize a multi-gigabyte heap allocation before the length is rejected. Unencrypted messages are part of the unauthenticated MTProto handshake path, so no credentials or established session are required to reach the vulnerable code. Impact is limited to availability; there is no evidence of memory corruption, out-of-bounds access, or code execution. ### Patches Fixed in **v0.145.1** by validating `dataLen` against the remaining buffer length before allocation (commit `9d5d1f31e`). ### Workarounds Upgrade to v0.145.1 or later. There is no in-process workaround for affected versions short of avoiding exposure of the unauthenticated MTProto parsing path to untrusted peers.

Source published: 28 Jul 2026 22:15:28 UTC
Source modified: 18 Aug 2026 17:24:12 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH

osv · GO-2026-6138

Published

Unbounded memory allocation in proto.UnencryptedMessage.Decode in github.com/gotd/td

Source published: 18 Aug 2026 16:38:10 UTC
Source modified: 18 Aug 2026 17:15:27 UTC
Observed here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.