CVE-2026-71397 json
Unbounded request body accumulation on streaming RPCs causes memory exhaustion in grpc_server
published 2026-11-06 2 d ago modified 2026-11-06 2 d ago also EEF-CVE-2026-71397 , GHSA-vx6q-cr5q-945g , EUVD-2026-118499
- cvss
- 8.2
- version 4.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
Allocation of Resources Without Limits or Throttling vulnerability in elixir-grpc grpc_server allows unauthenticated attackers to exhaust memory and crash the node via an oversized client-streaming or bidirectional-streaming request body.
The streaming read clause of 'Elixir.GRPC.Server.Adapters.Cowboy.Handler':info/3 (grpc_server/lib/grpc/server/adapters/cowboy/handler.ex) never checks the configured max_body_size. Only the unary read path enforces that cap. 'Elixir.GRPC.Server.Adapters.Cowboy':reading_stream/1 (grpc_server/lib/grpc/server/adapters/cowboy.ex) appends every received chunk to its buffer until a complete length-prefixed message arrives. A client can declare a very large message and send it across many small HTTP/2 DATA frames, and the server buffers all of it.
This issue affects grpc_server: from 1.0.0 before 1.0.6.
Patch / fix
- hex grpc_server 1.0.6
- elixir-grpc grpc_server 1.0.6
Exploit prediction
0.32% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.2 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| CNA | 4.0 | 8.2 | CVSS:4.0/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 |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| hex | grpc_server | >=1.0.0, <1.0.6 |
1.0.6 |
Affected products
- elixir-grpc grpc_server
Classification
- Weakness
-
- CWE-770 Allocation of Resources Without Limits or Throttling
References
-
github.com
/elixir-grpc/grpc/commit/49e18c3ec6bb9afe2f712caad3dbab5c56a68a00
related, web
-
github.com
/elixir-grpc/grpc/commit/0b663ca53dbf0f36f7f67ff1d0026f4482a18915
patch
-
github.com
/elixir-grpc/grpc/security/advisories/GHSA-vx6q-cr5q-945g
vendor-advisory, related, advisory
-
cna.erlef.org
/cves/CVE-2026-71397.html
related, web
-
osv.dev
/vulnerability/EEF-CVE-2026-71397
related
-
hex.pm
/packages/grpc_server
package
Sources
- CVE List CVE-2026-71397
- NVD CVE-2026-71397
- OSV EEF-CVE-2026-71397
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