CVE-2026-121808
Memory exhaustion via compressed Erlang terms in the elixir-grpc Erlpack codec
Description
Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in elixir-grpc grpc_core and grpc allows unauthenticated attackers to exhaust server memory via a compressed Erlang external term in a gRPC message body. GRPC.Codec.Erlpack.decode/2 (grpc_core/lib/grpc/codec/erlpack.ex, and lib/grpc/codec/erlpack.ex before the package split) passes the message body to :erlang.binary_to_term/2. That function inflates a compressed term in full before it returns. The codec sets no limit on the decoded size, and its type checks run only on the decoded term. The server's max_body_size limit counts the compressed bytes of the request. A request with Content-Type: application/grpc+erlpack can therefore make the server allocate a term much larger than the request body. This issue affects grpc: from 0.4.0 before 1.0.0; grpc_core: from 1.0.0 before 1.1.0.
INFO
Published Date :
Nov. 13, 2026, 4:17 p.m.
Last Modified :
Nov. 13, 2026, 4:17 p.m.
Remotely Exploit :
Yes !
Source :
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Affected Products
The following products are affected by CVE-2026-121808
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db | ||||
| CVSS 4.0 | HIGH | 6b3ad84c-e1a6-4bf7-a703-f496b71e49db |
Solution
- Update elixir-grpc to version 1.0.0 or later.
- Update grpc_core to version 1.1.0 or later.
- Apply relevant patches if available.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-121808.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-121808 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-121808
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-121808 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-121808 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Nov. 13, 2026
Action Type Old Value New Value Added Description Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in elixir-grpc grpc_core and grpc allows unauthenticated attackers to exhaust server memory via a compressed Erlang external term in a gRPC message body. GRPC.Codec.Erlpack.decode/2 (grpc_core/lib/grpc/codec/erlpack.ex, and lib/grpc/codec/erlpack.ex before the package split) passes the message body to :erlang.binary_to_term/2. That function inflates a compressed term in full before it returns. The codec sets no limit on the decoded size, and its type checks run only on the decoded term. The server's max_body_size limit counts the compressed bytes of the request. A request with Content-Type: application/grpc+erlpack can therefore make the server allocate a term much larger than the request body. This issue affects grpc: from 0.4.0 before 1.0.0; grpc_core: from 1.0.0 before 1.1.0. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-409 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/121xxx/CVE-2026-121808.json">CVE-2026-121808</a> Added Reference https://cna.erlef.org/cves/CVE-2026-121808.html Added Reference https://github.com/elixir-grpc/grpc/commit/0332faae5f5e132314794dbfdae5edecbccea292 Added Reference https://github.com/elixir-grpc/grpc/commit/25bcc569fe2cc4478531a6c546c923205fc751c9 Added Reference https://github.com/elixir-grpc/grpc/commit/d6bc56ac75dfb6c02db2099909210a37c9be8db6 Added Reference https://github.com/elixir-grpc/grpc/security/advisories/GHSA-xxp9-7hp4-rqwp Added Reference https://osv.dev/vulnerability/EEF-CVE-2026-121808