Security readout for executives and security teams
Plain-English summary
CVE-2021-36155 is a denial-of-service issue in gRPC Swift 1.1.0 and earlier. A remote attacker could make the message reader allocate excessively large buffers, exhausting resources and disrupting affected services. No active exploitation is reported in the provided sources.
Executive priority
Treat as a service availability risk. Prioritize if gRPC Swift is used in exposed production services, but avoid emergency escalation without confirmed exposure or exploitation evidence.
Technical view
LengthPrefixedMessageReader in gRPC Swift 1.1.0 and earlier allocates buffers based on arbitrary message lengths, allowing uncontrolled resource consumption. The available source bundle does not provide CVSS, CWE, exploit maturity, or a specific fixed version.
Likely exposure
Exposure is likely limited to applications or services using gRPC Swift 1.1.0 or earlier, especially where remote clients can send gRPC messages to the service.
Exploitation context
The vulnerability is remotely triggerable denial of service based on the CVE description. The source bundle marks KEV as false and provides no evidence of public exploitation or weaponized activity.
Researcher notes
The bundle identifies the vulnerable component and behavior, but lacks CVSS, CWE, affected CPEs, and explicit remediation details. Validate against the GitHub advisory and release notes before closing exposure.
Mitigation direction
- Inventory services using gRPC Swift and identify deployed versions.
- Review the gRPC Swift advisory and releases for the vendor-supported fix path.
- Prioritize remediation for internet-facing or partner-facing gRPC endpoints.
- Reduce untrusted access to affected gRPC services where operationally feasible.
Validation and detection
- Check dependency manifests and lockfiles for gRPC Swift 1.1.0 or earlier.
- Confirm running builds and containers use the expected gRPC Swift version.
- Map which affected services accept remote gRPC messages.
- Record advisory review results, including any fixed version named by the vendor.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-36155 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/grpc/grpc-swift/releasesCVE reference · x_refsource_MISC
- https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35303CVE reference · x_refsource_MISC
- https://github.com/grpc/grpc-swift/security/advisories/GHSA-rxmj-hg9v-vp3pCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.