CVE-2021-36154
Uncontrolled Recursion in HTTP2ToRawGRPCServerCodec
HTTP2ToRawGRPCServerCodec in gRPC Swift 1.1.1 and earlier allows remote attackers to deny service via the delivery of many small messages within a single HTTP/2 frame, leading to Uncontrolled Recursion and stack consumption.
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
HTTP2ToRawGRPCServerCodec in gRPC Swift 1.1.1 and earlier allows remote attackers to deny service via the delivery of many small messages within a single HTTP/2 frame, leading to Uncontrolled Recursion and stack consumption.
- Record
CVE-2021-36154- 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 - Weakness
- CWE-674
- Updated
- 2026-11-02
CVE List No score
HTTP2ToRawGRPCServerCodec in gRPC Swift 1.1.1 and earlier allows remote attackers to deny service via the delivery of many small messages within a single HTTP/2 frame, leading to Uncontrolled Recursion and stack consumption.
- Record
CVE-2021-36154- Updated
- 2026-11-02
EUVDEUVD-2023-1469 No score
HTTP2ToRawGRPCServerCodec in gRPC Swift 1.1.1 and earlier allows remote attackers to deny service via the delivery of many small messages within a single HTTP/2 frame, leading to Uncontrolled Recursion and stack consumption.
- Record
EUVD-2023-1469- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4rhq-vq24-88gw No score
Uncontrolled Recursion in HTTP2ToRawGRPCServerCodec
Impact
Affected gRPC Swift servers are vulnerable to uncontrolled recursion and stack consumption when parsing certain payloads. 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-4rhq-vq24-88gw- Weakness
- CWE-674
- Updated
- 2026-11-02
OSV
HTTP2ToRawGRPCServerCodec in gRPC Swift 1.1.1 and earlier allows remote attackers to deny service via the delivery of many small messages within a single HTTP/2 frame, leading to Uncontrolled Recursion and stack consumption.
- Record
CVE-2021-36154- 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-4rhq-vq24-88gw No score
Uncontrolled Recursion in HTTP2ToRawGRPCServerCodec
Impact
Affected gRPC Swift servers are vulnerable to uncontrolled recursion and stack consumption when parsing certain payloads. 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-4rhq-vq24-88gw- Weakness
- CWE-674
- 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-2021-36154 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.
References
github.com/grpc/grpc-swift/releases
bugs.chromium.org/p/oss-fuzz/issues/detail?id=35274
nvd.nist.gov/vuln/detail/CVE-2021-36154