CVE-2021-36153
Incomplete Internal State Distinction in GRPCWebToHTTP2ServerCodec
Mismanaged state in GRPCWebToHTTP2ServerCodec.swift in gRPC Swift 1.1.0 and 1.1.1 allows remote attackers to deny service by sending malformed requests.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
Mismanaged state in GRPCWebToHTTP2ServerCodec.swift in gRPC Swift 1.1.0 and 1.1.1 allows remote attackers to deny service by sending malformed requests.
- Record
CVE-2021-36153- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Updated
- 2026-11-02
CVE List No score
Mismanaged state in GRPCWebToHTTP2ServerCodec.swift in gRPC Swift 1.1.0 and 1.1.1 allows remote attackers to deny service by sending malformed requests.
- Record
CVE-2021-36153- Updated
- 2026-11-02
EUVDEUVD-2023-1664 No score
Mismanaged state in GRPCWebToHTTP2ServerCodec.swift in gRPC Swift 1.1.0 and 1.1.1 allows remote attackers to deny service by sending malformed requests.
- Record
EUVD-2023-1664- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-2jx2-qcm4-rf9h No score
Incomplete Internal State Distinction in GRPCWebToHTTP2ServerCodec
Impact
Affected gRPC Swift servers are vulnerable to precondition failures when parsing certain gRPC Web requests. This may lead to a denial of service.
Patches
The problem has been fixed in 1.2.0.
Workarounds
No workaround is available. Users must upgrade.
- Record
GHSA-2jx2-qcm4-rf9h- Updated
- 2026-11-02
OSV
Mismanaged state in GRPCWebToHTTP2ServerCodec.swift in gRPC Swift 1.1.0 and 1.1.1 allows remote attackers to deny service by sending malformed requests.
- Record
CVE-2021-36153- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-2jx2-qcm4-rf9h No score
Incomplete Internal State Distinction in GRPCWebToHTTP2ServerCodec
Impact
Affected gRPC Swift servers are vulnerable to precondition failures when parsing certain gRPC Web requests. This may lead to a denial of service.
Patches
The problem has been fixed in 1.2.0.
Workarounds
No workaround is available. Users must upgrade.
- Record
GHSA-2jx2-qcm4-rf9h- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/grpc/grpc-swiftSwiftURL |
before 1.2.0 | 1.2.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-36153 is a high vulnerability (CVSS 7.5) in Linuxfoundation Grpc Swift, published July 9, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.08%, the 81st percentile. Fixed in github.com/grpc/grpc-swift 1.2.0.